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Net::SSLeay(3)	      User Contributed Perl Documentation	Net::SSLeay(3)

NAME
       Net::SSLeay - Perl extension for	using OpenSSL

SYNOPSIS
	 use Net::SSLeay qw(get_https post_https sslcat	make_headers make_form);

	 ($page) = get_https('www.bacus.pt', 443, '/');			# Case 1

	 ($page, $response, %reply_headers)
		= get_https('www.bacus.pt', 443, '/',			# Case 2
		       make_headers(User-Agent => 'Cryptozilla/5.0b1',
				    Referer    => 'https://www.bacus.pt'
		       ));

	 ($page, $result, %headers) =					# Case 2b
		= get_https('www.bacus.pt', 443, '/protected.html',
		     make_headers(Authorization	=>
				  'Basic ' . MIME::Base64::encode("$user:$pass",''))
		     );

	 ($page, $response, %reply_headers)
		= post_https('www.bacus.pt', 443, '/foo.cgi', '',	# Case 3
		       make_form(OK   => '1',
				 name => 'Sampo'
		       ));

	 $reply	= sslcat($host,	$port, $request);			# Case 4

	 ($reply, $err,	$server_cert) =	sslcat($host, $port, $request);	# Case 5

	 $Net::SSLeay::trace = 2;  # 0=no debugging, 1=ciphers,	2=trace, 3=dump	data

	 Net::SSLeay::initialize(); # Initialize ssl library once

DESCRIPTION
       Net::SSLeay module contains perl	bindings to openssl
       (<http://www.openssl.org>) library.

       COMPATIBILITY NOTE: Net::SSLeay cannot be built with pre-0.9.3 openssl.
       It is strongly recommended to use at least 0.9.7	(as older versions are
       not tested during development). Some low	level API functions may	be
       available with certain openssl versions.

       It is compatible	with OpenSSL 1.0 and 1.1. Some functions are not
       available under OpenSSL 1.1.

       Net::SSLeay module basically comprise of:

       o   High	level functions	for accessing web servers (by using
	   HTTP/HTTPS)

       o   Low level API (mostly mapped	1:1 to openssl's C functions)

       o   Convenience functions (related to low level API but with more perl
	   friendly interface)

       There is	also a related module called Net::SSLeay::Handle included in
       this distribution that you might	want to	use instead. It	has its	own
       pod documentation.

   High	level functions	for accessing web servers
       This module offers some high level convenience functions	for accessing
       web pages on SSL	servers	(for symmetry, the same	API is offered for
       accessing http servers, too), an	"sslcat()" function for	writing	your
       own clients, and	finally	access to the SSL api of the SSLeay/OpenSSL
       package so you can write	servers	or clients for more complicated
       applications.

       For high	level functions	it is most convenient to import	them into your
       main namespace as indicated in the synopsis.

       Basic set of functions

       o   get_https

       o   post_https

       o   put_https

       o   head_https

       o   do_https

       o   sslcat

       o   https_cat

       o   make_form

       o   make_headers

       Case 1 (in SYNOPSIS) demonstrates the typical invocation	of get_https()
       to fetch	an HTML	page from secure server. The first argument provides
       the hostname or IP in dotted decimal notation of	the remote server to
       contact.	The second argument is the TCP port at the remote end (your
       own port	is picked arbitrarily from high	numbered ports as usual	for
       TCP). The third argument	is the URL of the page without the host	name
       part. If	in doubt consult the HTTP specifications at
       <http://www.w3c.org>.

       Case 2 (in SYNOPSIS) demonstrates full fledged use of "get_https()". As
       can be seen, "get_https()" parses the response and response headers and
       returns them as a list, which can be captured in	a hash for later
       reference. Also a fourth	argument to "get_https()" is used to insert
       some additional headers in the request. "make_headers()"	is a function
       that will convert a list	or hash	to such	headers. By default
       "get_https()" supplies "Host" (to make virtual hosting easy) and
       "Accept"	(reportedly needed by IIS) headers.

       Case 2b (in SYNOPSIS) demonstrates how to get a password	protected
       page. Refer to the HTTP protocol	specifications for further details
       (e.g. RFC-2617).

       Case 3 (in SYNOPSIS) invokes "post_https()" to submit a HTML/CGI	form
       to a secure server. The first four arguments are	equal to "get_https()"
       (note that the empty string ('')	is passed as header argument).	The
       fifth argument is the contents of the form formatted according to CGI
       specification.  Do not post UTF-8 data as content: use utf8::downgrade
       first. In this case the helper function "make_https()" is used to do
       the formatting, but you could pass any string. "post_https()"
       automatically adds "Content-Type" and "Content-Length" headers to the
       request.

       Case 4 (in SYNOPSIS) shows the fundamental "sslcat()" function
       (inspired in spirit by the "netcat" utility :-).	It's your swiss	army
       knife that allows you to	easily contact servers,	send some data,	and
       then get	the response. You are responsible for formatting the data and
       parsing the response - "sslcat()" is just a transport.

       Case 5 (in SYNOPSIS) is a full invocation of "sslcat()" which allows
       the return of errors as well as the server (peer) certificate.

       The $trace global variable can be used to control the verbosity of the
       high level functions. Level 0 guarantees	silence, level 1 (the default)
       only emits error	messages.

       Alternate versions of high-level	API

       o   get_https3

       o   post_https3

       o   put_https3

       o   get_https4

       o   post_https4

       o   put_https4

       The above mentioned functions actually return the response headers as a
       list, which only	gets converted to hash upon assignment (this
       assignment looses information if	the same header	occurs twice, as may
       be the case with	cookies). There	are also other variants	of the
       functions that return unprocessed headers and that return a reference
       to a hash.

	 ($page, $response, @headers) =	get_https('www.bacus.pt', 443, '/');
	 for ($i = 0; $i < $#headers; $i+=2) {
	     print "$headers[$i] = " . $headers[$i+1] .	"\n";
	 }

	 ($page, $response, $headers, $server_cert)
	   = get_https3('www.bacus.pt',	443, '/');
	 print "$headers\n";

	 ($page, $response, $headers_ref)
	   = get_https4('www.bacus.pt',	443, '/');
	 for $k	(sort keys %{$headers_ref}) {
	     for $v (@{$$headers_ref{$k}}) {
		 print "$k = $v\n";
	     }
	 }

       All of the above	code fragments accomplish the same thing: display all
       values of all headers. The API functions	ending in "3" return the
       headers simply as a scalar string and it	is up to the application to
       split them up. The functions ending in "4" return a reference to	a hash
       of arrays (see perlref and perllol if you are not familiar with complex
       perl data structures). To access	a single value of such a header	hash
       you would do something like

	 print $$headers_ref{COOKIE}[0];

       Variants	3 and 4	also allow you to discover the server certificate in
       case you	would like to store or display it, e.g.

	 ($p, $resp, $hdrs, $server_cert) = get_https3('www.bacus.pt', 443, '/');
	 if (!defined($server_cert) || ($server_cert ==	0)) {
	     warn "Subject Name: undefined, Issuer  Name: undefined";
	 } else	{
	     warn 'Subject Name: '
		 . Net::SSLeay::X509_NAME_oneline(
			Net::SSLeay::X509_get_subject_name($server_cert))
		     . 'Issuer	Name: '
			 . Net::SSLeay::X509_NAME_oneline(
				Net::SSLeay::X509_get_issuer_name($server_cert));
	 }

       Beware that this	method only allows after the fact verification of the
       certificate: by the time	"get_https3()" has returned the	https request
       has already been	sent to	the server, whether you	decide to trust	it or
       not. To do the verification correctly you must either employ the
       OpenSSL certificate verification	framework or use the lower level API
       to first	connect	and verify the certificate and only then send the http
       data. See the implementation of "ds_https3()" for guidance on how to do
       this.

       Using client certificates

       Secure web communications are encrypted using symmetric crypto keys
       exchanged using encryption based	on the certificate of the server.
       Therefore in all	SSL connections	the server must	have a certificate.
       This serves both	to authenticate	the server to the clients and to
       perform the key exchange.

       Sometimes it is necessary to authenticate the client as well. Two
       options are available: HTTP basic authentication	and a client side
       certificate. The	basic authentication over HTTPS	is actually quite safe
       because HTTPS guarantees	that the password will not travel in the
       clear. Never-the-less, problems like easily guessable passwords remain.
       The client certificate method involves authentication of	the client at
       the SSL level using a certificate. For this to work, both the client
       and the server have certificates	(which typically are different)	and
       private keys.

       The API functions outlined above	accept additional arguments that allow
       one to supply the client	side certificate and key files.	The format of
       these files is the same as used for server certificates and the caveat
       about encrypting	private	keys applies.

	 ($page, $result, %headers) =					# 2c
		= get_https('www.bacus.pt', 443, '/protected.html',
		     make_headers(Authorization	=>
				  'Basic ' . MIME::Base64::encode("$user:$pass",'')),
		     '', $mime_type6, $path_to_crt7, $path_to_key8);

	 ($page, $response, %reply_headers)
		= post_https('www.bacus.pt', 443, '/foo.cgi',		# 3b
		     make_headers('Authorization' =>
				  'Basic ' . MIME::Base64::encode("$user:$pass",'')),
		     make_form(OK   => '1', name => 'Sampo'),
		     $mime_type6, $path_to_crt7, $path_to_key8);

       Case 2c (in SYNOPSIS) demonstrates getting a password protected page
       that also requires a client certificate,	i.e. it	is possible to use
       both authentication methods simultaneously.

       Case 3b (in SYNOPSIS) is	a full blown POST to a secure server that
       requires	both password authentication and a client certificate, just
       like in case 2c.

       Note: The client	will not send a	certificate unless the server requests
       one.  This is typically achieved	by setting the verify mode to
       "VERIFY_PEER" on	the server:

	 Net::SSLeay::set_verify(ssl, Net::SSLeay::VERIFY_PEER,	0);

       See "perldoc ~openssl/doc/ssl/SSL_CTX_set_verify.pod" for a full
       description.

       Working through a web proxy

       o   set_proxy

       "Net::SSLeay" can use a web proxy to make its connections. You need to
       first set the proxy host	and port using "set_proxy()" and then just use
       the normal API functions, e.g:

	 Net::SSLeay::set_proxy('gateway.myorg.com', 8080);
	 ($page) = get_https('www.bacus.pt', 443, '/');

       If your proxy requires authentication, you can supply a username	and
       password	as well

	 Net::SSLeay::set_proxy('gateway.myorg.com', 8080, 'joe', 'salainen');
	 ($page, $result, %headers) =
		= get_https('www.bacus.pt', 443, '/protected.html',
		     make_headers(Authorization	=>
				  'Basic ' . MIME::Base64::encode("susie:pass",''))
		     );

       This example demonstrates the case where	we authenticate	to the proxy
       as "joe"	and to the final web server as "susie".	Proxy authentication
       requires	the "MIME::Base64" module to work.

       HTTP (without S)	API

       o   get_http

       o   post_http

       o   tcpcat

       o   get_httpx

       o   post_httpx

       o   tcpxcat

       Over the	years it has become clear that it would	be convenient to use
       the light-weight	flavour	API of "Net::SSLeay" for normal	HTTP as	well
       (see "LWP" for the heavy-weight object-oriented approach). In fact it
       would be	nice to	be able	to flip	https on and off on the	fly. Thus
       regular HTTP support was	evolved.

	 use Net::SSLeay qw(get_http post_http tcpcat
			     get_httpx post_httpx tcpxcat
			     make_headers make_form);

	 ($page, $result, %headers)
		= get_http('www.bacus.pt', 443,	'/protected.html',
		     make_headers(Authorization	=>
				  'Basic ' . MIME::Base64::encode("$user:$pass",''))
		     );

	 ($page, $response, %reply_headers)
		= post_http('www.bacus.pt', 443, '/foo.cgi', '',
		       make_form(OK   => '1',
				 name => 'Sampo'
		       ));

	 ($reply, $err)	= tcpcat($host,	$port, $request);

	 ($page, $result, %headers)
		= get_httpx($usessl, 'www.bacus.pt', 443, '/protected.html',
		     make_headers(Authorization	=>
				  'Basic ' . MIME::Base64::encode("$user:$pass",''))
		     );

	 ($page, $response, %reply_headers)
		= post_httpx($usessl, 'www.bacus.pt', 443, '/foo.cgi', '',
		       make_form(OK   => '1',  name => 'Sampo' ));

	 ($reply, $err,	$server_cert) =	tcpxcat($usessl, $host,	$port, $request);

       As can be seen, the "x" family of APIs takes as the first argument a
       flag which indicates whether SSL	is used	or not.

   Certificate verification and	Certificate Revocation Lists (CRLs)
       OpenSSL supports	the ability to verify peer certificates. It can	also
       optionally check	the peer certificate against a Certificate Revocation
       List (CRL) from the certificates	issuer.	A CRL is a file, created by
       the certificate issuer that lists all the certificates that it
       previously signed, but which it now revokes. CRLs are in	PEM format.

       You can enable "Net::SSLeay CRL"	checking like this:

		   &Net::SSLeay::X509_STORE_set_flags
		       (&Net::SSLeay::CTX_get_cert_store($ssl),
			&Net::SSLeay::X509_V_FLAG_CRL_CHECK);

       After setting this flag,	if OpenSSL checks a peer's certificate,	then
       it will attempt to find a CRL for the issuer. It	does this by looking
       for a specially named file in the search	directory specified by
       CTX_load_verify_locations.  CRL files are named with the	hash of	the
       issuer's	subject	name, followed by ".r0", ".r1" etc.  For example
       "ab1331b2.r0", "ab1331b2.r1". It	will read all the .r files for the
       issuer, and then	check for a revocation of the peer certificate in all
       of them.	 (You can also force it	to look	in a specific named CRL	file.,
       see below).  You	can find out the hash of the issuer subject name in a
       CRL with

	       openssl crl -in crl.pem -hash -noout

       If the peer certificate does not	pass the revocation list, or if	no CRL
       is found, then the handshaking fails with an error.

       You can also force OpenSSL to look for CRLs in one or more arbitrarily
       named files.

	   my $bio = Net::SSLeay::BIO_new_file($crlfilename, 'r');
	   my $crl = Net::SSLeay::PEM_read_bio_X509_CRL($bio);
	   if ($crl) {
	       Net::SSLeay::X509_STORE_add_crl(
		    Net::SSLeay::CTX_get_cert_store($ssl, $crl)
	       );
	   } else {
	       error reading CRL....
	   }

       Usually the URLs	where you can download the CRLs	is contained in	the
       certificate itself and you can extract them with

	   my @url = Net::SSLeay::P_X509_get_crl_distribution_points($cert)

       But there is no automatic downloading of	the CRLs and often these CRLs
       are too huge to just download them to verify a single certificate.
       Also, these CRLs	are often in DER format	which you need to convert to
       PEM before you can use it:

	   openssl crl -in crl.der -inform der -out crl.pem

       So as an	alternative for	faster and timely revocation checks you	better
       use the Online Status Revocation	Protocol (OCSP).

   Certificate verification and	Online Status Revocation Protocol (OCSP)
       While checking for revoked certificates is possible and fast with
       Certificate Revocation Lists, you need to download the complete and
       often huge list before you can verify a single certificate.

       A faster	way is to ask the CA to	check the revocation of	just a single
       or a few	certificates using OCSP. Basically you generate	for each
       certificate an OCSP_CERTID based	on the certificate itself and its
       issuer, put the ids togetether into an OCSP_REQUEST and send the
       request to the URL given	in the certificate.

       As a result you get back	an OCSP_RESPONSE and need to check the status
       of the response,	check that it is valid (e.g. signed by the CA) and
       finally extract the information about each OCSP_CERTID to find out if
       the certificate is still	valid or got revoked.

       With Net::SSLeay	this can be done like this:

	   # get id(s) for given certs,	like from get_peer_certificate
	   # or	get_peer_cert_chain. This will croak if
	   # - one tries to make an OCSP_CERTID	for a self-signed certificate
	   # - the issuer of the certificate cannot be found in	the SSL	objects
	   #   store, nor in the current certificate chain
	   my $cert = Net::SSLeay::get_peer_certificate($ssl);
	   my $id = eval { Net::SSLeay::OCSP_cert2ids($ssl,$cert) };
	   die "failed to make OCSP_CERTID: $@"	if $@;

	   # create OCSP_REQUEST from id(s)
	   # Multiple can be put into the same request,	if the same OCSP responder
	   # is	responsible for	them.
	   my $req = Net::SSLeay::OCSP_ids2req($id);

	   # determine URI of OCSP responder
	   my $uri = Net::SSLeay::P_X509_get_ocsp_uri($cert);

	   # Send stringified OCSP_REQUEST with	POST to	$uri.
	   # We	can ignore certificate verification for	https, because the OCSP
	   # response itself is	signed.
	   my $ua = HTTP::Tiny->new(verify_SSL => 0);
	   my $res = $ua->request( 'POST',$uri,	{
	       headers => { 'Content-type' => 'application/ocsp-request' },
	       content => Net::SSLeay::i2d_OCSP_REQUEST($req)
	   });
	   my $content = $res && $res->{success} && $res->{content}
	       or die "query failed";

	   # Extract OCSP_RESPONSE.
	   # this will croak if	the string is not an OCSP_RESPONSE
	   my $resp = eval { Net::SSLeay::d2i_OCSP_RESPONSE($content) };

	   # Check status of response.
	   my $status =	Net::SSLeay::OCSP_response_status($resp);
	   if ($status != Net::SSLeay::OCSP_RESPONSE_STATUS_SUCCESSFUL())
	       die "OCSP response failed: ".
		   Net::SSLeay::OCSP_response_status_str($status);
	   }

	   # Verify signature of response and if nonce matches request.
	   # This will croak if	there is a nonce in the	response, but it does not match
	   # the request. It will return false if the signature	could not be verified,
	   # in	which case details can be retrieved with Net::SSLeay::ERR_get_error.
	   # It	will not complain if the response does not contain a nonce, which is
	   # usually the case with pre-signed responses.
	   if (	! eval { Net::SSLeay::OCSP_response_verify($ssl,$resp,$req) }) {
	       die "OCSP response verification failed";
	   }

	   # Extract information from OCSP_RESPONSE for	each of	the ids.

	   # If	called in scalar context it will return	the time (as time_t), when the
	   # next update is due	(minimum of all	successful responses inside $resp). It
	   # will croak	on the following problems:
	   # - response	is expired or not yet valid
	   # - no response for given OCSP_CERTID
	   # - certificate status is not good (e.g. revoked or unknown)
	   if (	my $nextupd = eval { Net::SSLeay::OCSP_response_results($resp,$id) }) {
	       warn "certificate is valid, next	update in ".
		   ($nextupd-time())." seconds\n";
	   } else {
	       die "certificate	is not valid: $@";
	   }

	   # But in array context it will return detailed information about each given
	   # OCSP_CERTID instead croaking on errors:
	   # if	no @ids	are given it will return information about all single responses
	   # in	the OCSP_RESPONSE
	   my @results = Net::SSLeay::OCSP_response_results($resp,@ids);
	   for my $r (@results)	{
	       print Dumper($r);
	       # @results are in the same order	as the @ids and	contain:
	       # $r->[0] - OCSP_CERTID
	       # $r->[1] - undef if no error (certificate good)	OR error message as string
	       # $r->[2] - hash	with details:
	       #   thisUpdate -	time_t of this single response
	       #   nextUpdate -	time_t when update is expected
	       #   statusType -	integer:
	       #      V_OCSP_CERTSTATUS_GOOD(0)
	       #      V_OCSP_CERTSTATUS_REVOKED(1)
	       #      V_OCSP_CERTSTATUS_UNKNOWN(2)
	       #   revocationTime - time_t (only if revoked)
	       #   revocationReason - integer (only if revoked)
	       #   revocationReason_str	- reason as string (only if revoked)
	   }

       To further speed	up certificate revocation checking one can use a TLS
       extension to instruct the server	to staple the OCSP response:

	   # set TLS extension before doing SSL_connect
	   Net::SSLeay::set_tlsext_status_type($ssl,
	       Net::SSLeay::TLSEXT_STATUSTYPE_ocsp());

	   # setup callback to verify OCSP response
	   my $cert_valid = undef;
	   Net::SSLeay::CTX_set_tlsext_status_cb($context,sub {
	       my ($ssl,$resp) = @_;
	       if (!$resp) {
		   # Lots of servers don't return an OCSP response.
		   # In	this case we must check	the OCSP status	outside	the SSL
		   # handshake.
		   warn	"server	did not	return stapled OCSP response\n";
		   return 1;
	       }
	       # verify	status
	       my $status = Net::SSLeay::OCSP_response_status($resp);
	       if ($status != Net::SSLeay::OCSP_RESPONSE_STATUS_SUCCESSFUL()) {
		   warn	"OCSP response failure:	$status\n";
		   return 1;
	       }
	       # verify	signature - we have no OCSP_REQUEST here to check nonce
	       if (!eval { Net::SSLeay::OCSP_response_verify($ssl,$resp) }) {
		   warn	"OCSP response verify failed\n";
		   return 1;
	       }
	       # check if the certificate is valid
	       # we should check here against the peer_certificate
	       my $cert	= Net::SSLeay::get_peer_certificate();
	       my $certid = eval { Net::SSLeay::OCSP_cert2ids($ssl,$cert) } or do {
		   warn	"cannot	get certid from	cert: $@";
		   $cert_valid = -1;
		   return 1;
	       };

	       if ( $nextupd = eval {
		   Net::SSLeay::OCSP_response_results($resp,$certid) })	{
		   warn	"certificate not revoked\n";
		   $cert_valid = 1;
	       } else {
		   warn	"certificate not valid:	$@";
		   $cert_valid = 0;
	       }
	   });

	   # do	SSL handshake here
	   ....
	   # check if certificate revocation was checked already
	   if (	! defined $cert_valid) {
	       # check revocation outside of SSL handshake by asking OCSP responder
	       ...
	   } elsif ( ! $cert_valid ) {
	       die "certificate	not valid - closing SSL	connection";
	   } elsif ( $cert_valid<0 ) {
	       die "cannot verify certificate revocation - self-signed ?";
	   } else {
	       # everything fine
	       ...
	   }

   Using Net::SSLeay in	multi-threaded applications
       IMPORTANT: versions 1.42	or earlier are not thread-safe!

       Net::SSLeay module implements all necessary stuff to be ready for
       multi-threaded environment - it requires	openssl-0.9.7 or newer.	The
       implementation fully follows thread safety related requirements of
       openssl library(see <http://www.openssl.org/docs/crypto/threads.html>).

       If you are about	to use Net::SSLeay (or any other module	based on
       Net::SSLeay) in multi-threaded perl application it is recommended to
       follow this best-practice:

       Initialization

       Load and	initialize Net::SSLeay module in the main thread:

	   use threads;
	   use Net::SSLeay;

	   Net::SSLeay::load_error_strings();
	   Net::SSLeay::SSLeay_add_ssl_algorithms();
	   Net::SSLeay::randomize();

	   sub do_master_job {
	     #... call whatever	from Net::SSLeay
	   }

	   sub do_worker_job {
	     #... call whatever	from Net::SSLeay
	   }

	   #start threads
	   my $master  = threads->new(\&do_master_job, 'param1', 'param2');
	   my @workers = threads->new(\&do_worker_job, 'arg1', 'arg2') for (1..10);

	   #waiting for	all threads to finish
	   $_->join() for (threads->list);

       NOTE: Openssl's "int SSL_library_init(void)" function (which is also
       aliased as "SSLeay_add_ssl_algorithms", "OpenSSL_add_ssl_algorithms"
       and "add_ssl_algorithms") is not	re-entrant and multiple	calls can
       cause a crash in	threaded application.  Net::SSLeay implements flags
       preventing repeated calls to this function, therefore even multiple
       initialization via Net::SSLeay::SSLeay_add_ssl_algorithms() should work
       without trouble.

       Using callbacks

       Do not use callbacks across threads (the	module blocks cross-thread
       callback	operations and throws a	warning). Always do the	callback
       setup, callback use and callback	destruction within the same thread.

       Using openssl elements

       All openssl elements (X509, SSL_CTX, ...) can be	directly passed
       between threads.

	   use threads;
	   use Net::SSLeay;

	   Net::SSLeay::load_error_strings();
	   Net::SSLeay::SSLeay_add_ssl_algorithms();
	   Net::SSLeay::randomize();

	   sub do_job {
	     my	$context = shift;
	     Net::SSLeay::CTX_set_default_passwd_cb($context, sub { "secret" });
	     #...
	   }

	   my $c = Net::SSLeay::CTX_new();
	   threads->create(\&do_job, $c);

       Or:

	   use threads;
	   use Net::SSLeay;

	   my $context;	#does not need to be 'shared'

	   Net::SSLeay::load_error_strings();
	   Net::SSLeay::SSLeay_add_ssl_algorithms();
	   Net::SSLeay::randomize();

	   sub do_job {
	     Net::SSLeay::CTX_set_default_passwd_cb($context, sub { "secret" });
	     #...
	   }

	   $context = Net::SSLeay::CTX_new();
	   threads->create(\&do_job);

       Using other perl	modules	based on Net::SSLeay

       It should be fine to use	any other module based on Net::SSLeay (like
       IO::Socket::SSL)	in multi-threaded applications.	It is generally
       recommended to do any global initialization of such a module in the
       main thread before calling "threads->new(..)" or	"threads->create(..)"
       but it might differ module by module.

       To be safe you can load and init	Net::SSLeay explicitly in the main
       thread:

	   use Net::SSLeay;
	   use Other::SSLeay::Based::Module;

	   Net::SSLeay::load_error_strings();
	   Net::SSLeay::SSLeay_add_ssl_algorithms();
	   Net::SSLeay::randomize();

       Or even safer:

	   use Net::SSLeay;
	   use Other::SSLeay::Based::Module;

	   BEGIN {
	     Net::SSLeay::load_error_strings();
	     Net::SSLeay::SSLeay_add_ssl_algorithms();
	     Net::SSLeay::randomize();
	   }

       Combining Net::SSLeay with other	modules	linked with openssl

       BEWARE: This might be a big trouble! This is not	guaranteed be thread-
       safe!

       There are many other (XS) modules linked	directly to openssl library
       (like Crypt::SSLeay).

       As it is	expected that also "another" module will call
       "SSLeay_add_ssl_algorithms" at some point we have again a trouble with
       multiple	openssl	initialization by Net::SSLeay and "another" module.

       As you can expect Net::SSLeay is	not able to avoid multiple
       initialization of openssl library called	by "another" module, thus you
       have to handle this on your own (in some	cases it might not be possible
       at all to avoid this).

       Threading with get_https	and friends

       The convenience functions get_https, post_https etc all initialize the
       SSL library by calling Net::SSLeay::initialize which does the
       conventional library initialization:

	   Net::SSLeay::load_error_strings();
	   Net::SSLeay::SSLeay_add_ssl_algorithms();
	   Net::SSLeay::randomize();

       Net::SSLeay::initialize initializes the SSL library at most once.  You
       can override the	Net::SSLeay::initialize	function if you	desire some
       other type of initialization behaviour by get_https and friends.	 You
       can call	Net::SSLeay::initialize	from your own code if you desire this
       conventional library initialization.

   Convenience routines
       To be used with Low level API

	   Net::SSLeay::randomize($rn_seed_file,$additional_seed);
	   Net::SSLeay::set_cert_and_key($ctx, $cert_path, $key_path);
	   $cert = Net::SSLeay::dump_peer_certificate($ssl);
	   Net::SSLeay::ssl_write_all($ssl, $message) or die "ssl write	failure";
	   $got	= Net::SSLeay::ssl_read_all($ssl) or die "ssl read failure";

	   $got	= Net::SSLeay::ssl_read_CRLF($ssl [, $max_length]);
	   $got	= Net::SSLeay::ssl_read_until($ssl [, $delimit [, $max_length]]);
	   Net::SSLeay::ssl_write_CRLF($ssl, $message);

       o   randomize

	   seeds the openssl PRNG with "/dev/urandom" (see the top of
	   "SSLeay.pm" for how to change or configure this) and	optionally
	   with	user provided data. It is very important to properly seed your
	   random numbers, so do not forget to call this. The high level API
	   functions automatically call	"randomize()" so it is not needed with
	   them. See also caveats.

       o   set_cert_and_key

	   takes two file names	as arguments and sets the certificate and
	   private key to those. This can be used to set either	server
	   certificates	or client certificates.

       o   dump_peer_certificate

	   allows you to get a plaintext description of	the certificate	the
	   peer	(usually the server) presented to us.

       o   ssl_read_all

	   see ssl_write_all (below)

       o   ssl_write_all

	   "ssl_read_all()" and	"ssl_write_all()" provide true blocking
	   semantics for these operations (see limitation, below, for
	   explanation). These are much	preferred to the low level API
	   equivalents (which implement	BSD blocking semantics). The message
	   argument to "ssl_write_all()" can be	a reference. This is helpful
	   to avoid unnecessary	copying	when writing something big, e.g:

	       $data = 'A' x 1000000000;
	       Net::SSLeay::ssl_write_all($ssl,	\$data)	or die "ssl write failed";

       o   ssl_read_CRLF

	   uses	"ssl_read_all()" to read in a line terminated with a carriage
	   return followed by a	linefeed (CRLF).  The CRLF is included in the
	   returned scalar.

       o   ssl_read_until

	   uses	"ssl_read_all()" to read from the SSL input stream until it
	   encounters a	programmer specified delimiter.	 If the	delimiter is
	   undefined, $/ is used.  If $/ is undefined, "\n" is used.  One can
	   optionally set a maximum length of bytes to read from the SSL input
	   stream.

       o   ssl_write_CRLF

	   writes $message and appends CRLF to the SSL output stream.

   Initialization
       In order	to use the low level API you should start your programs	with
       the following incantation:

	       use Net::SSLeay qw(die_now die_if_ssl_error);
	       Net::SSLeay::load_error_strings();
	       Net::SSLeay::SSLeay_add_ssl_algorithms();    # Important!
	       Net::SSLeay::ENGINE_load_builtin_engines();  # If you want built-in engines
	       Net::SSLeay::ENGINE_register_all_complete(); # If you want built-in engines
	       Net::SSLeay::randomize();

   Error handling functions
       I can not emphasize the need to check for error enough. Use these
       functions even in the most simple programs, they	will reduce debugging
       time greatly. Do	not ask	questions on the mailing list without having
       first sprinkled these in	your code.

       o   die_now

       o   die_if_ssl_error

	   "die_now()" and "die_if_ssl_error()"	are used to conveniently print
	   the SSLeay error stack when something goes wrong:

		   Net::SSLeay::connect($ssl) or die_now("Failed SSL connect ($!)");

		   Net::SSLeay::write($ssl, "foo") or die_if_ssl_error("SSL write ($!)");

       o   print_errs

	   You can also	use "Net::SSLeay::print_errs()"	to dump	the error
	   stack without exiting the program. As can be	seen, your code
	   becomes much	more readable if you import the	error reporting
	   functions into your main name space.

   Sockets
       Perl uses file handles for all I/O. While SSLeay	has a quite flexible
       BIO mechanism and perl has an evolved PerlIO mechanism, this module
       still sticks to using file descriptors. Thus to attach SSLeay to	a
       socket you should use "fileno()"	to extract the underlying file
       descriptor:

	   Net::SSLeay::set_fd($ssl, fileno(S));   # Must use fileno

       You should also set $| to 1 to eliminate	STDIO buffering	so you do not
       get confused if you use perl I/O	functions to manipulate	your socket
       handle.

       If you need to select(2)	on the socket, go right	ahead, but be warned
       that OpenSSL does some internal buffering so SSL_read does not always
       return data even	if the socket selected for reading (just keep on
       selecting and trying to read). "Net::SSLeay" is no different from the C
       language	OpenSSL	in this	respect.

   Callbacks
       You can establish a per-context verify callback function	something like
       this:

	       sub verify {
		   my ($ok, $x509_store_ctx) = @_;
		   print "Verifying certificate...\n";
		       ...
		   return $ok;
	       }

       It is used like this:

	       Net::SSLeay::set_verify ($ssl, Net::SSLeay::VERIFY_PEER,	\&verify);

       Per-context callbacks for decrypting private keys are implemented.

	       Net::SSLeay::CTX_set_default_passwd_cb($ctx, sub	{ "top-secret" });
	       Net::SSLeay::CTX_use_PrivateKey_file($ctx, "key.pem",
						    Net::SSLeay::FILETYPE_PEM)
		   or die "Error reading private key";
	       Net::SSLeay::CTX_set_default_passwd_cb($ctx, undef);

       If Hello	Extensions are supported by your OpenSSL, a session secret
       callback	can be set up to be called when	a session secret is set	by
       openssl.

       Establish it like this:
	   Net::SSLeay::set_session_secret_cb($ssl, \&session_secret_cb,
       $somedata);

       It will be called like this:

	   sub session_secret_cb
	   {
	       my ($secret, \@cipherlist, \$preferredcipher, $somedata)	= @_;
	   }

       No other	callbacks are implemented. You do not need to use any callback
       for simple (i.e.	normal)	cases where the	SSLeay built-in	verify
       mechanism satisfies your	needs.

       It is required to reset these callbacks to undef	immediately after use
       to prevent memory leaks,	thread safety problems and crashes on exit
       that can	occur if different threads set different callbacks.

       If you want to use callback stuff, see examples/callback.pl! It's the
       only one	I am able to make work reliably.

   Low level API
       In addition to the high level functions outlined	above, this module
       contains	straight-forward access	to CRYPTO and SSL parts	of OpenSSL C
       API.

       See the "*.h" headers from OpenSSL C distribution for a list of low
       level SSLeay functions to call (check SSLeay.xs to see if some function
       has been	implemented). The module strips	the initial "SSL_" off of the
       SSLeay names.  Generally	you should use "Net::SSLeay::" in its place.

       Note that some functions	are prefixed with "P_" - these are very	close
       to the original API however contain some	kind of	a wrapper making its
       interface more perl friendly.

       For example:

       In C:

	       #include	<ssl.h>

	       err = SSL_set_verify (ssl, SSL_VERIFY_CLIENT_ONCE,
					  &your_call_back_here);

       In Perl:

	       use Net::SSLeay;

	       $err = Net::SSLeay::set_verify ($ssl,
					       Net::SSLeay::VERIFY_CLIENT_ONCE,
					       \&your_call_back_here);

       If the function does not	start with "SSL_" you should use the full
       function	name, e.g.:

	       $err = Net::SSLeay::ERR_get_error;

       The following new functions behave in perlish way:

	       $got = Net::SSLeay::read($ssl);
					   # Performs SSL_read,	but returns $got
					   # resized according to data received.
					   # Returns undef on failure.

	       Net::SSLeay::write($ssl,	$foo) || die;
					   # Performs SSL_write, but automatically
					   # figures out the size of $foo

       Low level API: Version related functions

       o   SSLeay

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before

	   Gives version number	(numeric) of underlaying openssl library.

	    my $ver_number = Net::SSLeay::SSLeay();
	    # returns: the number identifying the openssl release
	    #
	    # 0x00903100 => openssl-0.9.3
	    # 0x00904100 => openssl-0.9.4
	    # 0x00905100 => openssl-0.9.5
	    # 0x0090600f => openssl-0.9.6
	    # 0x0090601f => openssl-0.9.6a
	    # 0x0090602f => openssl-0.9.6b
	    # ...
	    # 0x009060df => openssl-0.9.6m
	    # 0x0090700f => openssl-0.9.7
	    # 0x0090701f => openssl-0.9.7a
	    # 0x0090702f => openssl-0.9.7b
	    # ...
	    # 0x009070df => openssl-0.9.7m
	    # 0x0090800f => openssl-0.9.8
	    # 0x0090801f => openssl-0.9.8a
	    # 0x0090802f => openssl-0.9.8b
	    # ...
	    # 0x0090814f => openssl-0.9.8t
	    # 0x1000000f => openssl-1.0.0
	    # 0x1000004f => openssl-1.0.0d
	    # 0x1000007f => openssl-1.0.0g

	   You can use it like this:

	     if	(Net::SSLeay::SSLeay() < 0x0090800f) {
	       die "you	need openssl-0.9.8 or higher";
	     }

       o   SSLeay_version

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before

	   Gives version number	(string) of underlaying	openssl	library.

	    my $ver_string = Net::SSLeay::SSLeay_version($type);
	    # $type
	    #	0 (=SSLEAY_VERSION) - e.g. 'OpenSSL 1.0.0d 8 Feb 2011'
	    #	2 (=SSLEAY_CFLAGS)  - e.g. 'compiler: gcc -D_WINDLL -DOPENSSL_USE_APPLINK .....'
	    #	3 (=SSLEAY_BUILT_ON)- e.g. 'built on: Fri May  6 00:00:46 GMT 2011'
	    #	4 (=SSLEAY_PLATFORM)- e.g. 'platform: mingw'
	    #
	    # returns: string

	    Net::SSLeay::SSLeay_version();
	    #is	equivalent to
	    Net::SSLeay::SSLeay_version(0);

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/SSLeay_version.html>

       Low level API: Initialization related functions

       o   library_init

	   Initialize SSL library by registering algorithms.

	    my $rv = Net::SSLeay::library_init();

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_library_init.html>

	   While the original function from OpenSSL always returns 1,
	   Net::SSLeay adds a wrapper around it	to make	sure that the OpenSSL
	   function is only called once.  Thus the function will return	1 if
	   initialization was done and 0 if not, i.e. if initialization	was
	   done	already	before.

       o   add_ssl_algorithms

	   The alias for "library_init"

	    Net::SSLeay::add_ssl_algorithms();

       o   OpenSSL_add_ssl_algorithms

	   The alias for "library_init"

	    Net::SSLeay::OpenSSL_add_ssl_algorithms();

       o   SSLeay_add_ssl_algorithms

	   The alias for "library_init"

	    Net::SSLeay::SSLeay_add_ssl_algorithms();

       o   load_error_strings

	   Registers the error strings for all libcrypto + libssl related
	   functions.

	    Net::SSLeay::load_error_strings();
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/ERR_load_crypto_strings.html>

       o   ERR_load_crypto_strings

	   Registers the error strings for all libcrypto functions. No need to
	   call	this function if you have already called "load_error_strings".

	    Net::SSLeay::ERR_load_crypto_strings();
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/ERR_load_crypto_strings.html>

       o   ERR_load_RAND_strings

	   Registers the error strings for RAND	related	functions. No need to
	   call	this function if you have already called "load_error_strings".

	    Net::SSLeay::ERR_load_RAND_strings();
	    #
	    # returns: no return value

       o   ERR_load_SSL_strings

	   Registers the error strings for SSL related functions. No need to
	   call	this function if you have already called "load_error_strings".

	    Net::SSLeay::ERR_load_SSL_strings();
	    #
	    # returns: no return value

       o   OpenSSL_add_all_algorithms

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Add algorithms to internal table.

	    Net::SSLeay::OpenSSL_add_all_algorithms();
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/OpenSSL_add_all_algorithms.html>

       o   OPENSSL_add_all_algorithms_conf

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Similar to "OpenSSL_add_all_algorithms" - will ALWAYS load the
	   config file

	    Net::SSLeay::OPENSSL_add_all_algorithms_conf();
	    #
	    # returns: no return value

       o   OPENSSL_add_all_algorithms_noconf

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Similar to "OpenSSL_add_all_algorithms" - will NEVER	load the
	   config file

	    Net::SSLeay::OPENSSL_add_all_algorithms_noconf();
	    #
	    # returns: no return value

       Low level API: ERR_* and	SSL_alert_* related functions

       NOTE: Please note that SSL_alert_* function have	"SSL_" part stripped
       from their names.

       o   ERR_clear_error

	   Clear the error queue.

	    Net::SSLeay::ERR_clear_error();
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/ERR_clear_error.html>

       o   ERR_error_string

	   Generates a human-readable string representing the error code
	   $error.

	    my $rv = Net::SSLeay::ERR_error_string($error);
	    # $error - (unsigned integer) error	code
	    #
	    # returns: string

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/ERR_error_string.html>

       o   ERR_get_error

	   Returns the earliest	error code from	the thread's error queue and
	   removes the entry.  This function can be called repeatedly until
	   there are no	more error codes to return.

	    my $rv = Net::SSLeay::ERR_get_error();
	    #
	    # returns: (unsigned integer) error	code

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/ERR_get_error.html>

       o   ERR_peek_error

	   Returns the earliest	error code from	the thread's error queue
	   without modifying it.

	    my $rv = Net::SSLeay::ERR_peek_error();
	    #
	    # returns: (unsigned integer) error	code

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/ERR_get_error.html>

       o   ERR_put_error

	   Adds	an error code to the thread's error queue. It signals that the
	   error of $reason code reason	occurred in function $func of library
	   $lib, in line number	$line of $file.

	    Net::SSLeay::ERR_put_error($lib, $func, $reason, $file, $line);
	    # $lib - (integer) library id (check openssl/err.h for constants e.g. ERR_LIB_SSL)
	    # $func - (integer)	function id (check openssl/ssl.h for constants e.g. SSL_F_SSL23_READ)
	    # $reason -	(integer) reason id (check openssl/ssl.h for constants e.g. SSL_R_SSL_HANDSHAKE_FAILURE)
	    # $file - (string) file name
	    # $line - (integer)	line number in $file
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/ERR_put_error.html> and
	   <http://www.openssl.org/docs/crypto/err.html>

       o   alert_desc_string

	   Returns a two letter	string as a short form describing the reason
	   of the alert	specified by value.

	    my $rv = Net::SSLeay::alert_desc_string($value);
	    # $value - (integer) allert	id (check openssl/ssl.h	for SSL3_AD_* and TLS1_AD_* constants)
	    #
	    # returns: description string (2 letters)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_alert_type_string.html>

       o   alert_desc_string_long

	   Returns a string describing the reason of the alert specified by
	   value.

	    my $rv = Net::SSLeay::alert_desc_string_long($value);
	    # $value - (integer) allert	id (check openssl/ssl.h	for SSL3_AD_* and TLS1_AD_* constants)
	    #
	    # returns: description string

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_alert_type_string.html>

       o   alert_type_string

	   Returns a one letter	string indicating the type of the alert
	   specified by	value.

	    my $rv = Net::SSLeay::alert_type_string($value);
	    # $value - (integer) allert	id (check openssl/ssl.h	for SSL3_AD_* and TLS1_AD_* constants)
	    #
	    # returns: string (1 letter)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_alert_type_string.html>

       o   alert_type_string_long

	   Returns a string indicating the type	of the alert specified by
	   value.

	    my $rv = Net::SSLeay::alert_type_string_long($value);
	    # $value - (integer) allert	id (check openssl/ssl.h	for SSL3_AD_* and TLS1_AD_* constants)
	    #
	    # returns: string

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_alert_type_string.html>

       Low level API: SSL_METHOD_* related functions

       o   SSLv2_method

	   Returns SSL_METHOD structure	corresponding to SSLv2 method, the
	   return value	can be later used as a param of	"CTX_new_with_method".
	   Only	available where	supported by the underlying openssl.

	    my $rv = Net::SSLeay::SSLv2_method();
	    #
	    # returns: value corresponding to openssl's	SSL_METHOD structure (0	on failure)

       o   SSLv3_method

	   Returns SSL_METHOD structure	corresponding to SSLv3 method, the
	   return value	can be later used as a param of	"CTX_new_with_method".

	    my $rv = Net::SSLeay::SSLv3_method();
	    #
	    # returns: value corresponding to openssl's	SSL_METHOD structure (0	on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_new.html>

       o   TLSv1_method

	   Returns SSL_METHOD structure	corresponding to TLSv1 method, the
	   return value	can be later used as a param of	"CTX_new_with_method".

	    my $rv = Net::SSLeay::TLSv1_method();
	    #
	    # returns: value corresponding to openssl's	SSL_METHOD structure (0	on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_new.html>

       o   TLSv1_1_method

	   Returns SSL_METHOD structure	corresponding to TLSv1_1 method, the
	   return value	can be later used as a param of	"CTX_new_with_method".
	   Only	available where	supported by the underlying openssl.

	    my $rv = Net::SSLeay::TLSv1__1method();
	    #
	    # returns: value corresponding to openssl's	SSL_METHOD structure (0	on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_new.html>

       o   TLSv1_2_method

	   Returns SSL_METHOD structure	corresponding to TLSv1_2 method, the
	   return value	can be later used as a param of	"CTX_new_with_method".
	   Only	available where	supported by the underlying openssl.

	    my $rv = Net::SSLeay::TLSv1_2_method();
	    #
	    # returns: value corresponding to openssl's	SSL_METHOD structure (0	on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_new.html>

       Low level API: ENGINE_* related functions

       o   ENGINE_load_builtin_engines

	   Load	all bundled ENGINEs into memory	and make them visible.

	    Net::SSLeay::ENGINE_load_builtin_engines();
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/engine.html>

       o   ENGINE_register_all_complete

	   Register all	loaded ENGINEs for every algorithm they	collectively
	   implement.

	    Net::SSLeay::ENGINE_register_all_complete();
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/engine.html>

       o   ENGINE_set_default

	   Set default engine to $e + set its flags to $flags.

	    my $rv = Net::SSLeay::ENGINE_set_default($e, $flags);
	    # $e - value corresponding to openssl's ENGINE structure
	    # $flags - (integer) engine	flags
	    #	       flags value can be made by bitwise "OR"ing:
	    #	       0x0001 -	ENGINE_METHOD_RSA
	    #	       0x0002 -	ENGINE_METHOD_DSA
	    #	       0x0004 -	ENGINE_METHOD_DH
	    #	       0x0008 -	ENGINE_METHOD_RAND
	    #	       0x0010 -	ENGINE_METHOD_ECDH
	    #	       0x0020 -	ENGINE_METHOD_ECDSA
	    #	       0x0040 -	ENGINE_METHOD_CIPHERS
	    #	       0x0080 -	ENGINE_METHOD_DIGESTS
	    #	       0x0100 -	ENGINE_METHOD_STORE
	    #	       0x0200 -	ENGINE_METHOD_PKEY_METHS
	    #	       0x0400 -	ENGINE_METHOD_PKEY_ASN1_METHS
	    #	       Obvious all-or-nothing cases:
	    #	       0xFFFF -	ENGINE_METHOD_ALL
	    #	       0x0000 -	ENGINE_METHOD_NONE
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/crypto/engine.html>

       o   ENGINE_by_id

	   Get ENGINE by its identification $id.

	    my $rv = Net::SSLeay::ENGINE_by_id($id);
	    # $id - (string) engine identification e.g.	"dynamic"
	    #
	    # returns: value corresponding to openssl's	ENGINE structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/engine.html>

       Low level API: EVP_PKEY_* related functions

       o   EVP_PKEY_copy_parameters

	   Copies the parameters from key $from	to key $to.

	    my $rv = Net::SSLeay::EVP_PKEY_copy_parameters($to,	$from);
	    # $to - value corresponding	to openssl's EVP_PKEY structure
	    # $from - value corresponding to openssl's EVP_PKEY	structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/EVP_PKEY_cmp.html>

       o   EVP_PKEY_new

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Creates a new EVP_PKEY structure.

	    my $rv = Net::SSLeay::EVP_PKEY_new();
	    #
	    # returns: value corresponding to openssl's	EVP_PKEY structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/EVP_PKEY_new.html>

       o   EVP_PKEY_free

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Free	an allocated EVP_PKEY structure.

	    Net::SSLeay::EVP_PKEY_free($pkey);
	    # $pkey - value corresponding to openssl's EVP_PKEY	structure
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/EVP_PKEY_new.html>

       o   EVP_PKEY_assign_RSA

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Set the key referenced by $pkey to $key

	   NOTE: No reference counter will be increased, i.e. $key will	be
	   freed if $pkey is freed.

	    my $rv = Net::SSLeay::EVP_PKEY_assign_RSA($pkey, $key);
	    # $pkey - value corresponding to openssl's EVP_PKEY	structure
	    # $key - value corresponding to openssl's RSA structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/EVP_PKEY_assign_RSA.html>

       o   EVP_PKEY_assign_EC_KEY

	   COMPATIBILITY: not available	in Net-SSLeay-1.74 and before

	   Set the key referenced by $pkey to $key

	   NOTE: No reference counter will be increased, i.e. $key will	be
	   freed if $pkey is freed.

	    my $rv = Net::SSLeay::EVP_PKEY_assign_EC_KEY($pkey,	$key);
	    # $pkey - value corresponding to openssl's EVP_PKEY	structure
	    # $key - value corresponding to openssl's EC_KEY structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/EVP_PKEY_assign_EC_KEY.html>

       o   EVP_PKEY_bits

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns the size of the key $pkey in	bits.

	    my $rv = Net::SSLeay::EVP_PKEY_bits($pkey);
	    # $pkey - value corresponding to openssl's EVP_PKEY	structure
	    #
	    # returns: size in bits

       o   EVP_PKEY_size

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns the maximum size of a signature in bytes. The actual
	   signature may be smaller.

	    my $rv = Net::SSLeay::EVP_PKEY_size($pkey);
	    # $pkey - value corresponding to openssl's EVP_PKEY	structure
	    #
	    # returns: the maximum size	in bytes

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/EVP_SignInit.html>

       o   EVP_PKEY_id

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-1.0.0

	   Returns $pkey type (integer value of	corresponding NID).

	    my $rv = Net::SSLeay::EVP_PKEY_id($pkey);
	    # $pkey - value corresponding to openssl's EVP_PKEY	structure
	    #
	    # returns: (integer) key type

	   Example:

	    my $pubkey = Net::SSLeay::X509_get_pubkey($x509);
	    my $type = Net::SSLeay::EVP_PKEY_id($pubkey);
	    print Net::SSLeay::OBJ_nid2sn($type);	      #prints e.g. 'rsaEncryption'

       Low level API: PEM_* related functions

       Check openssl doc <http://www.openssl.org/docs/crypto/pem.html>

       o   PEM_read_bio_X509

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Loads PEM formatted X509 certificate	via given BIO structure.

	    my $rv = Net::SSLeay::PEM_read_bio_X509($bio);
	    # $bio - value corresponding to openssl's BIO structure
	    #
	    # returns: value corresponding to openssl's	X509 structure (0 on failure)

	   Example:

	    my $bio = Net::SSLeay::BIO_new_file($filename, 'r');
	    my $x509 = Net::SSLeay::PEM_read_bio_X509($bio);
	    Net::SSLeay::BIO_free($bio);

       o   PEM_read_bio_X509_REQ

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Loads PEM formatted X509_REQ	object via given BIO structure.

	    my $rv = Net::SSLeay::PEM_read_bio_X509_REQ($bio, $x=NULL, $cb=NULL, $u=NULL);
	    # $bio - value corresponding to openssl's BIO structure
	    #
	    # returns: value corresponding to openssl's	X509_REQ structure (0 on failure)

	   Example:

	    my $bio = Net::SSLeay::BIO_new_file($filename, 'r');
	    my $x509_req = Net::SSLeay::PEM_read_bio_X509_REQ($bio);
	    Net::SSLeay::BIO_free($bio);

       o   PEM_read_bio_DHparams

	   Reads DH structure from BIO.

	    my $rv = Net::SSLeay::PEM_read_bio_DHparams($bio);
	    # $bio - value corresponding to openssl's BIO structure
	    #
	    # returns: value corresponding to openssl's	DH structure (0	on failure)

       o   PEM_read_bio_X509_CRL

	   Reads X509_CRL structure from BIO.

	    my $rv = Net::SSLeay::PEM_read_bio_X509_CRL($bio);
	    # $bio - value corresponding to openssl's BIO structure
	    #
	    # returns: value corresponding to openssl's	X509_CRL structure (0 on failure)

       o   PEM_read_bio_PrivateKey

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Loads PEM formatted private key via given BIO structure.

	    my $rv = Net::SSLeay::PEM_read_bio_PrivateKey($bio,	$cb, $data);
	    # $bio - value corresponding to openssl's BIO structure
	    # $cb - reference to perl callback function
	    # $data - data that	will be	passed to callback function (see examples below)
	    #
	    # returns: value corresponding to openssl's	EVP_PKEY structure (0 on failure)

	   Example:

	    my $bio = Net::SSLeay::BIO_new_file($filename, 'r');
	    my $privkey	= Net::SSLeay::PEM_read_bio_PrivateKey($bio); #ask for password	if needed
	    Net::SSLeay::BIO_free($bio);

	   To use password you have the	following options:

	    $privkey = Net::SSLeay::PEM_read_bio_PrivateKey($bio, \&callback_func); # use callback func	for getting password
	    $privkey = Net::SSLeay::PEM_read_bio_PrivateKey($bio, \&callback_func, $data); # use callback_func + pass $data to callback_func
	    $privkey = Net::SSLeay::PEM_read_bio_PrivateKey($bio, undef, "secret"); # use password "secret"
	    $privkey = Net::SSLeay::PEM_read_bio_PrivateKey($bio, undef, "");	    # use empty	password

	   Callback function signature:

	    sub	callback_func {
	      my ($max_passwd_size, $rwflag, $data) = @_;
	      #	$max_passwd_size - maximum size	of returned password (longer values will be discarded)
	      #	$rwflag	- indicates whether we are loading (0) or storing (1) -	for PEM_read_bio_PrivateKey always 0
	      #	$data -	the data passed	to PEM_read_bio_PrivateKey as 3rd parameter

	      return "secret";
	    }

       o   PEM_get_string_X509

	   NOTE: Does not exactly correspond to	any low	level API function

	   Converts/exports X509 certificate to	string (PEM format).

	    Net::SSLeay::PEM_get_string_X509($x509);
	    # $x509 - value corresponding to openssl's X509 structure
	    #
	    # returns: string with $x509 in PEM	format

       o   PEM_get_string_PrivateKey

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Converts public key $pk into	PEM formatted string (optionally
	   protected with password).

	    my $rv = Net::SSLeay::PEM_get_string_PrivateKey($pk, $passwd, $enc_alg);
	    # $pk - value corresponding	to openssl's EVP_PKEY structure
	    # $passwd -	[optional] (string) password to	use for	key encryption
	    # $enc_alg - [optional] algorithm to use for key encryption	(default: DES_CBC) - value corresponding to openssl's EVP_CIPHER structure
	    #
	    # returns: PEM formatted string

	   Examples:

	    $pem_privkey = Net::SSLeay::PEM_get_string_PrivateKey($pk);
	    $pem_privkey = Net::SSLeay::PEM_get_string_PrivateKey($pk, "secret");
	    $pem_privkey = Net::SSLeay::PEM_get_string_PrivateKey($pk, "secret", Net::SSLeay::EVP_get_cipherbyname("DES-EDE3-CBC"));

       o   PEM_get_string_X509_CRL

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Converts X509_CRL object $x509_crl into PEM formatted string.

	    Net::SSLeay::PEM_get_string_X509_CRL($x509_crl);
	    # $x509_crl	- value	corresponding to openssl's X509_CRL structure
	    #
	    # returns: no return value

       o   PEM_get_string_X509_REQ

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Converts X509_REQ object $x509_crl into PEM formatted string.

	    Net::SSLeay::PEM_get_string_X509_REQ($x509_req);
	    # $x509_req	- value	corresponding to openssl's X509_REQ structure
	    #
	    # returns: no return value

       Low level API: d2i_* (DER format) related functions

       o   d2i_X509_bio

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Loads DER formatted X509 certificate	via given BIO structure.

	    my $rv = Net::SSLeay::d2i_X509_bio($bp);
	    # $bp - value corresponding	to openssl's BIO structure
	    #
	    # returns: value corresponding to openssl's	X509 structure (0 on failure)

	   Example:

	    my $bio = Net::SSLeay::BIO_new_file($filename, 'rb');
	    my $x509 = Net::SSLeay::d2i_X509_bio($bio);
	    Net::SSLeay::BIO_free($bio);

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/d2i_X509.html>

       o   d2i_X509_CRL_bio

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Loads DER formatted X509_CRL	object via given BIO structure.

	    my $rv = Net::SSLeay::d2i_X509_CRL_bio($bp);
	    # $bp - value corresponding	to openssl's BIO structure
	    #
	    # returns: value corresponding to openssl's	X509_CRL structure (0 on failure)

	   Example:

	    my $bio = Net::SSLeay::BIO_new_file($filename, 'rb');
	    my $x509_crl = Net::SSLeay::d2i_X509_CRL_bio($bio);
	    Net::SSLeay::BIO_free($bio);

       o   d2i_X509_REQ_bio

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Loads DER formatted X509_REQ	object via given BIO structure.

	    my $rv = Net::SSLeay::d2i_X509_REQ_bio($bp);
	    # $bp - value corresponding	to openssl's BIO structure
	    #
	    # returns: value corresponding to openssl's	X509_REQ structure (0 on failure)

	   Example:

	    my $bio = Net::SSLeay::BIO_new_file($filename, 'rb');
	    my $x509_req = Net::SSLeay::d2i_X509_REQ_bio($bio);
	    Net::SSLeay::BIO_free($bio);

       Low level API: PKCS12 related functions

       o   P_PKCS12_load_file

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Loads X509 certificate + private key	+ certificates of CA chain (if
	   present in PKCS12 file).

	    my ($privkey, $cert, @cachain) = Net::SSLeay::P_PKCS12_load_file($filename,	$load_chain, $password);
	    # $filename	- name of PKCS12 file
	    # $load_chain - [optional] whether load (1)	or not(0) CA chain (default: 0)
	    # $password	- [optional] password for private key
	    #
	    # returns: triplet ($privkey, $cert, @cachain)
	    #	       $privkey	- value	corresponding to openssl's EVP_PKEY structure
	    #	       $cert - value corresponding to openssl's	X509 structure
	    #	       @cachain	- array	of values corresponding	to openssl's X509 structure (empty if no CA chain in PKCS12)

	   IMPORTANT NOTE: after you do	the job	you need to call X509_free()
	   on $privkey + all members of	@cachain and EVP_PKEY_free() on
	   $privkey.

	   Examples:

	    my ($privkey, $cert) = Net::SSLeay::P_PKCS12_load_file($filename);
	    #or
	    my ($privkey, $cert) = Net::SSLeay::P_PKCS12_load_file($filename, 0, $password);
	    #or
	    my ($privkey, $cert, @cachain) = Net::SSLeay::P_PKCS12_load_file($filename,	1);
	    #or
	    my ($privkey, $cert, @cachain) = Net::SSLeay::P_PKCS12_load_file($filename,	1, $password);

	    #BEWARE: THIS IS WRONG - MEMORY LEAKS! (you	cannot free @cachain items)
	    my ($privkey, $cert) = Net::SSLeay::P_PKCS12_load_file($filename, 1, $password);

	   NOTE	With some combinations of Windows, perl, compiler and compiler
	   options, you	may see	a runtime error	"no OPENSSL_Applink", when
	   calling Net::SSLeay::P_PKCS12_load_file. See	README.Win32 for more
	   details.

       Low level API: SESSION_*	related	functions

       o   d2i_SSL_SESSION

	   Transforms the external ASN1	representation of an SSL/TLS session,
	   stored as binary data at location pp	with length of $length,	into
	   an SSL_SESSION object.

	   ??? (does this function really work?)

	    my $rv = Net::SSLeay::d2i_SSL_SESSION($a, $pp, $length);
	    # $a - value corresponding to openssl's SSL_SESSION	structure
	    # $pp - pointer/buffer ???
	    # $length -	???
	    #
	    # returns: ???

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/d2i_SSL_SESSION.html>

       o   i2d_SSL_SESSION

	   Transforms the SSL_SESSION object in	into the ASN1 representation
	   and stores it into the memory location pointed to by	pp. The	length
	   of the resulting ASN1 representation	is returned.

	   ??? (does this function really work?)

	    my $rv = Net::SSLeay::i2d_SSL_SESSION($in, $pp);
	    # $in - value corresponding	to openssl's SSL_SESSION structure
	    # $pp - pointer/data ???
	    #
	    # returns: 1 on success, 0

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/d2i_SSL_SESSION.html>

       o   SESSION_new

	   Creates a new SSL_SESSION structure.

	    my $rv = Net::SSLeay::SESSION_new();
	    #
	    # returns: value corresponding to openssl's	SSL_SESSION structure (0 on failure)

       o   SESSION_free

	   Free	an allocated SSL_SESSION structure.

	    Net::SSLeay::SESSION_free($ses);
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_SESSION_free.html>

       o   SESSION_cmp

	   Compare two SSL_SESSION structures.

	    my $rv = Net::SSLeay::SESSION_cmp($sesa, $sesb);
	    # $sesa - value corresponding to openssl's SSL_SESSION structure
	    # $sesb - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: 0 if the	two structures are the same

	   NOTE: Not available in openssl 1.0 or later

       o   SESSION_get_app_data

	   Can be used to get application defined value/data.

	    my $rv = Net::SSLeay::SESSION_get_app_data($ses);
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: string/buffer/pointer ???

       o   SESSION_set_app_data

	   Can be used to set some application defined value/data.

	    my $rv = Net::SSLeay::SESSION_set_app_data($s, $a);
	    # $s - value corresponding to openssl's SSL_SESSION	structure
	    # $a - (string/buffer/pointer ???) data
	    #
	    # returns: ???

       o   SESSION_get_ex_data

	   Is used to retrieve the information for $idx	from session $ses.

	    my $rv = Net::SSLeay::SESSION_get_ex_data($ses, $idx);
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    # $idx - (integer) index for application specific data
	    #
	    # returns: pointer to ???

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_SESSION_get_ex_new_index.html>

       o   SESSION_set_ex_data

	   Is used to store application	data at	arg for	idx into the session
	   object.

	    my $rv = Net::SSLeay::SESSION_set_ex_data($ss, $idx, $data);
	    # $ss - value corresponding	to openssl's SSL_SESSION structure
	    # $idx - (integer) ???
	    # $data - (pointer)	???
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_SESSION_get_ex_new_index.html>

       o   SESSION_get_ex_new_index

	   Is used to register a new index for application specific data.

	    my $rv = Net::SSLeay::SESSION_get_ex_new_index($argl, $argp, $new_func, $dup_func, $free_func);
	    # $argl - (long) ???
	    # $argp - (pointer)	???
	    # $new_func	- function pointer ??? (CRYPTO_EX_new *)
	    # $dup_func	- function pointer ??? (CRYPTO_EX_dup *)
	    # $free_func - function pointer ???	(CRYPTO_EX_free	*)
	    #
	    # returns: (integer) ???

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_SESSION_get_ex_new_index.html>

       o   SESSION_get_master_key

	   NOTE: Does not exactly correspond to	any low	level API function

	   Returns 'master_key'	value from SSL_SESSION structure $s

	    Net::SSLeay::SESSION_get_master_key($s);
	    # $s - value corresponding to openssl's SSL_SESSION	structure
	    #
	    # returns: master key (binary data)

       o   SESSION_set_master_key

	   Sets	'master_key' value for SSL_SESSION structure $s

	    Net::SSLeay::SESSION_set_master_key($s, $key);
	    # $s - value corresponding to openssl's SSL_SESSION	structure
	    # $key - master key	(binary	data)
	    #
	    # returns: no return value

	   Not available with OpenSSL 1.1 and later.  Code that	previously
	   used
		  SESSION_set_master_key must now set $secret in the
	   session_secret
		  callback set with SSL_set_session_secret_cb.

       o   SESSION_get_time

	   Returns the time at which the session s was established.  The time
	   is given in seconds since 1.1.1970.

	    my $rv = Net::SSLeay::SESSION_get_time($s);
	    # $s - value corresponding to openssl's SSL_SESSION	structure
	    #
	    # returns: timestamp (seconds since	1.1.1970)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_SESSION_get_time.html>

       o   get_time

	   Technically the same	functionality as "SESSION_get_time".

	    my $rv = Net::SSLeay::get_time($s);

       o   SESSION_get_timeout

	   Returns the timeout value set for session $s	in seconds.

	    my $rv = Net::SSLeay::SESSION_get_timeout($s);
	    # $s - value corresponding to openssl's SSL_SESSION	structure
	    #
	    # returns: timeout (in seconds)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_SESSION_get_time.html>

       o   get_timeout

	   Technically the same	functionality as "SESSION_get_timeout".

	    my $rv = Net::SSLeay::get_timeout($s);

       o   SESSION_print

	   NOTE: Does not exactly correspond to	any low	level API function

	   Prints session details (e.g.	protocol version, cipher, session-id
	   ...)	to BIO.

	    my $rv = Net::SSLeay::SESSION_print($fp, $ses);
	    # $fp - value corresponding	to openssl's BIO structure
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: 1 on success, 0 on failure

	   You have to use necessary BIO functions like	this:

	    # let us have $ssl corresponding to	openssl's SSL structure
	    my $ses = Net::SSLeay::get_session($ssl);
	    my $bio = Net::SSLeay::BIO_new(&Net::SSLeay::BIO_s_mem);
	    Net::SSLeay::SESSION_print($bio, $ses);
	    print Net::SSLeay::BIO_read($bio);

       o   SESSION_print_fp

	   Prints session details (e.g.	protocol version, cipher, session-id
	   ...)	to file	handle.

	    my $rv = Net::SSLeay::SESSION_print_fp($fp,	$ses);
	    # $fp - perl file handle
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: 1 on success, 0 on failure

	   Example:

	    # let us have $ssl corresponding to	openssl's SSL structure
	    my $ses = Net::SSLeay::get_session($ssl);
	    open my $fh, ">", "output.txt";
	    Net::SSLeay::SESSION_print_fp($fh,$ses);

       o   SESSION_set_time

	   Replaces the	creation time of the session s with the	chosen value
	   $t (seconds since 1.1.1970).

	    my $rv = Net::SSLeay::SESSION_set_time($ses, $t);
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    # $t - time	value
	    #
	    # returns: 1 on success

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_SESSION_get_time.html>

       o   set_time

	   Technically the same	functionality as "SESSION_set_time".

	    my $rv = Net::SSLeay::set_time($ses, $t);

       o   SESSION_set_timeout

	   Sets	the timeout value for session s	in seconds to $t.

	    my $rv = Net::SSLeay::SESSION_set_timeout($s, $t);
	    # $s - value corresponding to openssl's SSL_SESSION	structure
	    # $t - timeout (in seconds)
	    #
	    # returns: 1 on success

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_SESSION_get_time.html>

       o   set_timeout

	   Technically the same	functionality as "SESSION_set_timeout".

	    my $rv = Net::SSLeay::set_timeout($ses, $t);

       Low level API: SSL_CTX_*	related	functions

       NOTE: Please note that the function described in	this chapter have
       "SSL_" part stripped from their original	openssl	names.

       o   CTX_add_client_CA

	   Adds	the CA name extracted from $cacert to the list of CAs sent to
	   the client when requesting a	client certificate for $ctx.

	    my $rv = Net::SSLeay::CTX_add_client_CA($ctx, $cacert);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $cacert -	value corresponding to openssl's X509 structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_client_CA_list.html>

       o   CTX_add_extra_chain_cert

	   Adds	the certificate	$x509 to the certificate chain presented
	   together with the certificate. Several certificates can be added
	   one after the other.

	    my $rv = Net::SSLeay::CTX_add_extra_chain_cert($ctx, $x509);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $x509 - value corresponding to openssl's X509 structure
	    #
	    # returns: 1 on success, check out the error stack to find out the reason for failure otherwise

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_add_extra_chain_cert.html>

       o   CTX_add_session

	   Adds	the session $ses to the	context	$ctx.

	    my $rv = Net::SSLeay::CTX_add_session($ctx,	$ses);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_add_session.html>

       o   CTX_callback_ctrl

	   ??? (more info needed)

	    my $rv = Net::SSLeay::CTX_callback_ctrl($ctx, $cmd,	$fp);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $cmd - (integer) command id
	    # $fp - (function pointer) ???
	    #
	    # returns: ???

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_ctrl.html>

       o   CTX_check_private_key

	   Checks the consistency of a private key with	the corresponding
	   certificate loaded into $ctx.

	    my $rv = Net::SSLeay::CTX_check_private_key($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   CTX_ctrl

	   Internal handling function for SSL_CTX objects.

	   BEWARE: openssl doc says: This function should never	be called
	   directly!

	    my $rv = Net::SSLeay::CTX_ctrl($ctx, $cmd, $larg, $parg);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $cmd - (integer) command id
	    # $larg - (integer)	long ???
	    # $parg - (string/pointer) ???
	    #
	    # returns: (long) result of	given command ???

	    #valid $cmd	values
	     1 - SSL_CTRL_NEED_TMP_RSA
	     2 - SSL_CTRL_SET_TMP_RSA
	     3 - SSL_CTRL_SET_TMP_DH
	     4 - SSL_CTRL_SET_TMP_ECDH
	     5 - SSL_CTRL_SET_TMP_RSA_CB
	     6 - SSL_CTRL_SET_TMP_DH_CB
	     7 - SSL_CTRL_SET_TMP_ECDH_CB
	     8 - SSL_CTRL_GET_SESSION_REUSED
	     9 - SSL_CTRL_GET_CLIENT_CERT_REQUEST
	    10 - SSL_CTRL_GET_NUM_RENEGOTIATIONS
	    11 - SSL_CTRL_CLEAR_NUM_RENEGOTIATIONS
	    12 - SSL_CTRL_GET_TOTAL_RENEGOTIATIONS
	    13 - SSL_CTRL_GET_FLAGS
	    14 - SSL_CTRL_EXTRA_CHAIN_CERT
	    15 - SSL_CTRL_SET_MSG_CALLBACK
	    16 - SSL_CTRL_SET_MSG_CALLBACK_ARG
	    17 - SSL_CTRL_SET_MTU
	    20 - SSL_CTRL_SESS_NUMBER
	    21 - SSL_CTRL_SESS_CONNECT
	    22 - SSL_CTRL_SESS_CONNECT_GOOD
	    23 - SSL_CTRL_SESS_CONNECT_RENEGOTIATE
	    24 - SSL_CTRL_SESS_ACCEPT
	    25 - SSL_CTRL_SESS_ACCEPT_GOOD
	    26 - SSL_CTRL_SESS_ACCEPT_RENEGOTIATE
	    27 - SSL_CTRL_SESS_HIT
	    28 - SSL_CTRL_SESS_CB_HIT
	    29 - SSL_CTRL_SESS_MISSES
	    30 - SSL_CTRL_SESS_TIMEOUTS
	    31 - SSL_CTRL_SESS_CACHE_FULL
	    32 - SSL_CTRL_OPTIONS
	    33 - SSL_CTRL_MODE
	    40 - SSL_CTRL_GET_READ_AHEAD
	    41 - SSL_CTRL_SET_READ_AHEAD
	    42 - SSL_CTRL_SET_SESS_CACHE_SIZE
	    43 - SSL_CTRL_GET_SESS_CACHE_SIZE
	    44 - SSL_CTRL_SET_SESS_CACHE_MODE
	    45 - SSL_CTRL_GET_SESS_CACHE_MODE
	    50 - SSL_CTRL_GET_MAX_CERT_LIST
	    51 - SSL_CTRL_SET_MAX_CERT_LIST
	    52 - SSL_CTRL_SET_MAX_SEND_FRAGMENT
	    53 - SSL_CTRL_SET_TLSEXT_SERVERNAME_CB
	    54 - SSL_CTRL_SET_TLSEXT_SERVERNAME_ARG
	    55 - SSL_CTRL_SET_TLSEXT_HOSTNAME
	    56 - SSL_CTRL_SET_TLSEXT_DEBUG_CB
	    57 - SSL_CTRL_SET_TLSEXT_DEBUG_ARG
	    58 - SSL_CTRL_GET_TLSEXT_TICKET_KEYS
	    59 - SSL_CTRL_SET_TLSEXT_TICKET_KEYS
	    60 - SSL_CTRL_SET_TLSEXT_OPAQUE_PRF_INPUT
	    61 - SSL_CTRL_SET_TLSEXT_OPAQUE_PRF_INPUT_CB
	    62 - SSL_CTRL_SET_TLSEXT_OPAQUE_PRF_INPUT_CB_ARG
	    63 - SSL_CTRL_SET_TLSEXT_STATUS_REQ_CB
	    64 - SSL_CTRL_SET_TLSEXT_STATUS_REQ_CB_ARG
	    65 - SSL_CTRL_SET_TLSEXT_STATUS_REQ_TYPE
	    66 - SSL_CTRL_GET_TLSEXT_STATUS_REQ_EXTS
	    67 - SSL_CTRL_SET_TLSEXT_STATUS_REQ_EXTS
	    68 - SSL_CTRL_GET_TLSEXT_STATUS_REQ_IDS
	    69 - SSL_CTRL_SET_TLSEXT_STATUS_REQ_IDS
	    70 - SSL_CTRL_GET_TLSEXT_STATUS_REQ_OCSP_RESP
	    71 - SSL_CTRL_SET_TLSEXT_STATUS_REQ_OCSP_RESP
	    72 - SSL_CTRL_SET_TLSEXT_TICKET_KEY_CB
	    73 - DTLS_CTRL_GET_TIMEOUT
	    74 - DTLS_CTRL_HANDLE_TIMEOUT
	    75 - DTLS_CTRL_LISTEN
	    76 - SSL_CTRL_GET_RI_SUPPORT
	    77 - SSL_CTRL_CLEAR_OPTIONS
	    78 - SSL_CTRL_CLEAR_MODE

	    82 - SSL_CTRL_GET_EXTRA_CHAIN_CERTS
	    83 - SSL_CTRL_CLEAR_EXTRA_CHAIN_CERTS

	    88 - SSL_CTRL_CHAIN
	    89 - SSL_CTRL_CHAIN_CERT

	    90 - SSL_CTRL_GET_CURVES
	    91 - SSL_CTRL_SET_CURVES
	    92 - SSL_CTRL_SET_CURVES_LIST
	    93 - SSL_CTRL_GET_SHARED_CURVE
	    94 - SSL_CTRL_SET_ECDH_AUTO
	    97 - SSL_CTRL_SET_SIGALGS
	    98 - SSL_CTRL_SET_SIGALGS_LIST
	    99 - SSL_CTRL_CERT_FLAGS
	    100	- SSL_CTRL_CLEAR_CERT_FLAGS
	    101	- SSL_CTRL_SET_CLIENT_SIGALGS
	    102	- SSL_CTRL_SET_CLIENT_SIGALGS_LIST
	    103	- SSL_CTRL_GET_CLIENT_CERT_TYPES
	    104	- SSL_CTRL_SET_CLIENT_CERT_TYPES
	    105	- SSL_CTRL_BUILD_CERT_CHAIN
	    106	- SSL_CTRL_SET_VERIFY_CERT_STORE
	    107	- SSL_CTRL_SET_CHAIN_CERT_STORE
	    108	- SSL_CTRL_GET_PEER_SIGNATURE_NID
	    109	- SSL_CTRL_GET_SERVER_TMP_KEY
	    110	- SSL_CTRL_GET_RAW_CIPHERLIST
	    111	- SSL_CTRL_GET_EC_POINT_FORMATS
	    112	- SSL_CTRL_GET_TLSA_RECORD
	    113	- SSL_CTRL_SET_TLSA_RECORD
	    114	- SSL_CTRL_PULL_TLSA_RECORD

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_ctrl.html>

       o   CTX_flush_sessions

	   Causes a run	through	the session cache of $ctx to remove sessions
	   expired at time $tm.

	    Net::SSLeay::CTX_flush_sessions($ctx, $tm);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $tm - specifies the time which should be used for	the expiration test (seconds since 1.1.1970)
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_flush_sessions.html>

       o   CTX_free

	   Free	an allocated SSL_CTX object.

	    Net::SSLeay::CTX_free($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_free.html>

       o   CTX_get_app_data

	   Can be used to get application defined value/data.

	    my $rv = Net::SSLeay::CTX_get_app_data($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: string/buffer/pointer ???

       o   CTX_set_app_data

	   Can be used to set some application defined value/data.

	    my $rv = Net::SSLeay::CTX_set_app_data($ctx, $arg);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $arg - (string/buffer/pointer ???) data
	    #
	    # returns: ???

       o   CTX_get_cert_store

	   Returns the current certificate verification	storage.

	    my $rv = Net::SSLeay::CTX_get_cert_store($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: value corresponding to openssl's	X509_STORE structure (0	on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_cert_store.html>

       o   CTX_get_client_CA_list

	   Returns the list of client CAs explicitly set for $ctx using
	   "CTX_set_client_CA_list".

	    my $rv = Net::SSLeay::CTX_get_client_CA_list($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: value corresponding to openssl's	X509_NAME_STACK	structure (0 on	failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_client_CA_list.html>

       o   CTX_get_ex_data

	   Is used to retrieve the information for index $idx from $ctx.

	    my $rv = Net::SSLeay::CTX_get_ex_data($ssl,	$idx);
	    # $ssl - value corresponding to openssl's SSL_CTX structure
	    # $idx - (integer) index for application specific data
	    #
	    # returns: pointer to ???

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_get_ex_new_index.html>

       o   CTX_get_ex_new_index

	   Is used to register a new index for application specific data.

	    my $rv = Net::SSLeay::CTX_get_ex_new_index($argl, $argp, $new_func,	$dup_func, $free_func);
	    # $argl - (long) ???
	    # $argp - (pointer)	???
	    # $new_func	- function pointer ??? (CRYPTO_EX_new *)
	    # $dup_func	- function pointer ??? (CRYPTO_EX_dup *)
	    # $free_func - function pointer ???	(CRYPTO_EX_free	*)
	    #
	    # returns: (integer) ???

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_get_ex_new_index.html>

       o   CTX_get_mode

	   Returns the mode set	for ctx.

	    my $rv = Net::SSLeay::CTX_get_mode($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: mode (bitmask)

	    #to	decode the return value	(bitmask) use:
	    0x00000001 corresponds to SSL_MODE_ENABLE_PARTIAL_WRITE
	    0x00000002 corresponds to SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER
	    0x00000004 corresponds to SSL_MODE_AUTO_RETRY
	    0x00000008 corresponds to SSL_MODE_NO_AUTO_CHAIN
	    0x00000010 corresponds to SSL_MODE_RELEASE_BUFFERS
	    (note: some	of the bits might not be supported by older openssl versions)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_mode.html>

       o   CTX_set_mode

	   Adds	the mode set via bitmask in $mode to $ctx. Options already set
	   before are not cleared.

	    my $rv = Net::SSLeay::CTX_set_mode($ctx, $mode);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $mode - mode bitmask
	    #
	    # returns: the new mode bitmask after adding $mode

	   For bitmask details see "CTX_get_mode" (above).

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_mode.html>

       o   CTX_get_options

	   Returns the options (bitmask) set for $ctx.

	    my $rv = Net::SSLeay::CTX_get_options($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: options (bitmask)

	    #to	decode the return value	(bitmask) use:
	    0x00000001 corresponds to SSL_OP_MICROSOFT_SESS_ID_BUG
	    0x00000002 corresponds to SSL_OP_NETSCAPE_CHALLENGE_BUG
	    0x00000004 corresponds to SSL_OP_LEGACY_SERVER_CONNECT
	    0x00000008 corresponds to SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG
	    0x00000010 corresponds to SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG
	    0x00000020 corresponds to SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER
	    0x00000040 corresponds to SSL_OP_MSIE_SSLV2_RSA_PADDING
	    0x00000080 corresponds to SSL_OP_SSLEAY_080_CLIENT_DH_BUG
	    0x00000100 corresponds to SSL_OP_TLS_D5_BUG
	    0x00000200 corresponds to SSL_OP_TLS_BLOCK_PADDING_BUG
	    0x00000800 corresponds to SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS
	    0x80000FFF corresponds to SSL_OP_ALL
	    0x00001000 corresponds to SSL_OP_NO_QUERY_MTU
	    0x00002000 corresponds to SSL_OP_COOKIE_EXCHANGE
	    0x00004000 corresponds to SSL_OP_NO_TICKET
	    0x00008000 corresponds to SSL_OP_CISCO_ANYCONNECT
	    0x00010000 corresponds to SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
	    0x00020000 corresponds to SSL_OP_NO_COMPRESSION
	    0x00040000 corresponds to SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
	    0x00080000 corresponds to SSL_OP_SINGLE_ECDH_USE
	    0x00100000 corresponds to SSL_OP_SINGLE_DH_USE
	    0x00200000 corresponds to SSL_OP_EPHEMERAL_RSA
	    0x00400000 corresponds to SSL_OP_CIPHER_SERVER_PREFERENCE
	    0x00800000 corresponds to SSL_OP_TLS_ROLLBACK_BUG
	    0x01000000 corresponds to SSL_OP_NO_SSLv2
	    0x02000000 corresponds to SSL_OP_NO_SSLv3
	    0x04000000 corresponds to SSL_OP_NO_TLSv1
	    0x08000000 corresponds to SSL_OP_PKCS1_CHECK_1
	    0x10000000 corresponds to SSL_OP_PKCS1_CHECK_2
	    0x20000000 corresponds to SSL_OP_NETSCAPE_CA_DN_BUG
	    0x40000000 corresponds to SSL_OP_NETSCAPE_DEMO_CIPHER_CHANGE_BUG
	    0x80000000 corresponds to SSL_OP_CRYPTOPRO_TLSEXT_BUG
	    (note: some	of the bits might not be supported by older openssl versions)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_options.html>

       o   CTX_set_options

	   Adds	the options set	via bitmask in $options	to ctx.	Options
	   already set before are not cleared.

	    Net::SSLeay::CTX_set_options($ctx, $options);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $options - options bitmask
	    #
	    # returns: the new options bitmask after adding $options

	   For bitmask details see "CTX_get_options" (above).

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_options.html>

       o   CTX_get_quiet_shutdown

	   Returns the 'quiet shutdown'	setting	of $ctx.

	    my $rv = Net::SSLeay::CTX_get_quiet_shutdown($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: (integer) the current setting

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_quiet_shutdown.html>

       o   CTX_get_read_ahead

	    my $rv = Net::SSLeay::CTX_get_read_ahead($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: (integer) read_ahead value

       o   CTX_get_session_cache_mode

	   Returns the currently used cache mode (bitmask).

	    my $rv = Net::SSLeay::CTX_get_session_cache_mode($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: mode (bitmask)

	    #to	decode the return value	(bitmask) use:
	    0x0000 corresponds to SSL_SESS_CACHE_OFF
	    0x0001 corresponds to SSL_SESS_CACHE_CLIENT
	    0x0002 corresponds to SSL_SESS_CACHE_SERVER
	    0x0080 corresponds to SSL_SESS_CACHE_NO_AUTO_CLEAR
	    0x0100 corresponds to SSL_SESS_CACHE_NO_INTERNAL_LOOKUP
	    0x0200 corresponds to SSL_SESS_CACHE_NO_INTERNAL_STORE
	    (note: some	of the bits might not be supported by older openssl versions)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_session_cache_mode.html>

       o   CTX_set_session_cache_mode

	   Enables/disables session caching by setting the operational mode
	   for $ctx to $mode.

	    my $rv = Net::SSLeay::CTX_set_session_cache_mode($ctx, $mode);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $mode - mode (bitmask)
	    #
	    # returns: previously set cache mode

	   For bitmask details see "CTX_get_session_cache_mode"	(above).

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_session_cache_mode.html>

       o   CTX_get_timeout

	   Returns the currently set timeout value for $ctx.

	    my $rv = Net::SSLeay::CTX_get_timeout($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: timeout in seconds

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_timeout.html>

       o   CTX_get_verify_depth

	   Returns the verification depth limit	currently set in $ctx. If no
	   limit has been explicitly set, -1 is	returned and the default value
	   will	be used.",

	    my $rv = Net::SSLeay::CTX_get_verify_depth($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: depth limit currently set in $ctx, -1 if	no limit has been explicitly set

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_get_verify_mode.html>

       o   CTX_get_verify_mode

	   Returns the verification mode (bitmask) currently set in $ctx.

	    my $rv = Net::SSLeay::CTX_get_verify_mode($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: mode (bitmask)

	    #to	decode the return value	(bitmask) use:
	    0x00 corresponds to	SSL_VERIFY_NONE
	    0x01 corresponds to	SSL_VERIFY_PEER
	    0x02 corresponds to	SSL_VERIFY_FAIL_IF_NO_PEER_CERT
	    0x04 corresponds to	SSL_VERIFY_CLIENT_ONCE
	    (note: some	of the bits might not be supported by older openssl versions)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_get_verify_mode.html>

       o   CTX_set_verify

	   Sets	the verification flags for $ctx	to be $mode and	specifies the
	   verify_callback function to be used.

	    Net::SSLeay::CTX_set_verify($ctx, $mode, $callback);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $mode - mode (bitmask)
	    # $callback	- [optional] reference to perl callback	function
	    #
	    # returns: no return value

	   For bitmask details see "CTX_get_verify_mode" (above).

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_verify.html>

       o   CTX_load_verify_locations

	   Specifies the locations for $ctx, at	which CA certificates for
	   verification	purposes are located. The certificates available via
	   $CAfile and $CApath are trusted.

	    my $rv = Net::SSLeay::CTX_load_verify_locations($ctx, $CAfile, $CApath);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $CAfile -	(string) file of CA certificates in PEM	format,	the file can contain several CA	certificates (or '')
	    # $CApath -	(string) directory containing CA certificates in PEM format (or	'')
	    #
	    # returns: 1 on success, 0 on failure (check the error stack to find out the reason)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_load_verify_locations.html>

       o   CTX_need_tmp_RSA

	   Return the result of
	   "SSL_CTX_ctrl(ctx,SSL_CTRL_NEED_TMP_RSA,0,NULL)"

	    my $rv = Net::SSLeay::CTX_need_tmp_RSA($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: result of SSL_CTRL_NEED_TMP_RSA command

	   Not available with OpenSSL 1.1 and later.

       o   CTX_new

	   The same as "CTX_v23_new"

	    my $rv = Net::SSLeay::CTX_new();
	    #
	    # returns: value corresponding to openssl's	SSL_CTX	structure (0 on	failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_new.html>

	   Not available with OpenSSL 1.1 and later.

       o   CTX_v2_new

	   Creates a new SSL_CTX object	- based	on SSLv2_method() - as
	   framework to	establish TLS/SSL enabled connections.

	    my $rv = Net::SSLeay::CTX_v2_new();
	    #
	    # returns: value corresponding to openssl's	SSL_CTX	structure (0 on	failure)

       o   CTX_v23_new

	   Creates a new SSL_CTX object	- based	on SSLv23_method() - as
	   framework to	establish TLS/SSL enabled connections.

	    my $rv = Net::SSLeay::CTX_v23_new();
	    #
	    # returns: value corresponding to openssl's	SSL_CTX	structure (0 on	failure)

       o   CTX_v3_new

	   Creates a new SSL_CTX object	- based	on SSLv3_method() - as
	   framework to	establish TLS/SSL enabled connections.

	    my $rv = Net::SSLeay::CTX_v3_new();
	    #
	    # returns: value corresponding to openssl's	SSL_CTX	structure (0 on	failure)

       o   CTX_tlsv1_new

	   Creates a new SSL_CTX object	- based	on TLSv1_method() - as
	   framework to	establish TLS/SSL enabled connections.

	    my $rv = Net::SSLeay::CTX_tlsv1_new();
	    #
	    # returns: value corresponding to openssl's	SSL_CTX	structure (0 on	failure)

       o   CTX_tlsv1_1_new

	   Creates a new SSL_CTX object	- based	on TLSv1_1_method() - as
	   framework to	establish TLS/SSL enabled connections. Only available
	   where supported by the underlying openssl.

	    my $rv = Net::SSLeay::CTX_tlsv1_1_new();
	    #
	    # returns: value corresponding to openssl's	SSL_CTX	structure (0 on	failure)

       o   CTX_tlsv1_2_new

	   Creates a new SSL_CTX object	- based	on TLSv1_2_method() - as
	   framework to	establish TLS/SSL enabled connections. Only available
	   where supported by the underlying openssl.

	    my $rv = Net::SSLeay::CTX_tlsv1_2_new();
	    #
	    # returns: value corresponding to openssl's	SSL_CTX	structure (0 on	failure)

       o   CTX_new_with_method

	   Creates a new SSL_CTX object	based on $meth method

	    my $rv = Net::SSLeay::CTX_new_with_method($meth);
	    # $meth - value corresponding to openssl's SSL_METHOD structure
	    #
	    # returns: value corresponding to openssl's	SSL_CTX	structure (0 on	failure)

	    #example
	    my $ctx = Net::SSLeay::CTX_new_with_method(&Net::SSLeay::TLSv1_method);

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_new.html>

       o   CTX_remove_session

	   Removes the session $ses from the context $ctx.

	    my $rv = Net::SSLeay::CTX_remove_session($ctx, $ses);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_add_session.html>

       o   CTX_sess_accept

	    my $rv = Net::SSLeay::CTX_sess_accept($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of started SSL/TLS handshakes in server mode

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_accept_good

	    my $rv = Net::SSLeay::CTX_sess_accept_good($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of successfully established SSL/TLS sessions in server mode

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_accept_renegotiate

	    my $rv = Net::SSLeay::CTX_sess_accept_renegotiate($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of start renegotiations in server	mode

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_cache_full

	    my $rv = Net::SSLeay::CTX_sess_cache_full($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of sessions that were removed because the	maximum	session	cache size was exceeded

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_cb_hits

	    my $rv = Net::SSLeay::CTX_sess_cb_hits($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of successfully retrieved	sessions from the external session cache in server mode

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_connect

	    my $rv = Net::SSLeay::CTX_sess_connect($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of started SSL/TLS handshakes in client mode

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_connect_good

	    my $rv = Net::SSLeay::CTX_sess_connect_good($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of successfully established SSL/TLS sessions in client mode

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_connect_renegotiate

	    my $rv = Net::SSLeay::CTX_sess_connect_renegotiate($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of start renegotiations in client	mode

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_get_cache_size

	   Returns the currently valid session cache size.

	    my $rv = Net::SSLeay::CTX_sess_get_cache_size($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: current size

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_sess_set_cache_size.html>

       o   CTX_sess_hits

	    my $rv = Net::SSLeay::CTX_sess_hits($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of successfully reused sessions

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_misses

	    my $rv = Net::SSLeay::CTX_sess_misses($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of sessions proposed by clients that were	not found in the internal session cache	in server mode

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_number

	    my $rv = Net::SSLeay::CTX_sess_number($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: current number of sessions in the internal session cache

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_set_cache_size

	   Sets	the size of the	internal session cache of context $ctx to
	   $size.

	    Net::SSLeay::CTX_sess_set_cache_size($ctx, $size);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $size - cache size (0 = unlimited)
	    #
	    # returns: previously valid	size

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_sess_set_cache_size.html>

       o   CTX_sess_timeouts

	   Returns the number of sessions proposed by clients and either found
	   in the internal or external session cache in	server mode, but that
	   were	invalid	due to timeout.	These sessions are not included	in the
	   SSL_CTX_sess_hits count.

	    my $rv = Net::SSLeay::CTX_sess_timeouts($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of sessions

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sessions

	   Returns a pointer to	the lhash databases containing the internal
	   session cache for ctx.

	    my $rv = Net::SSLeay::CTX_sessions($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: value corresponding to openssl's	LHASH structure	(0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_sessions.html>

       o   CTX_set1_param

	   Applies X509	verification parameters	$vpm on	$ctx

	    my $rv = Net::SSLeay::CTX_set1_param($ctx, $vpm);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $vpm - value corresponding to openssl's X509_VERIFY_PARAM	structure
	    #
	    # returns: 1 on success, 0 on failure

       o   CTX_set_cert_store

	   Sets/replaces the certificate verification storage of $ctx to/with
	   $store.

	    Net::SSLeay::CTX_set_cert_store($ctx, $store);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $store - value corresponding to openssl's	X509_STORE structure
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_cert_store.html>

       o   CTX_set_cert_verify_callback

	   Sets	the verification callback function for $ctx. SSL objects that
	   are created from $ctx inherit the setting valid at the time when
	   "Net::SSLeay::new($ctx)" is called.

	    Net::SSLeay::CTX_set_cert_verify_callback($ctx, $func, $data);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $func - perl reference to	callback function
	    # $data - [optional] data that will	be passed to callback function when invoked
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_cert_verify_callback.html>

       o   CTX_set_cipher_list

	   Sets	the list of available ciphers for $ctx using the control
	   string $str.	 The list of ciphers is	inherited by all ssl objects
	   created from	$ctx.

	    my $rv = Net::SSLeay::CTX_set_cipher_list($s, $str);
	    # $s - value corresponding to openssl's SSL_CTX structure
	    # $str - (string) cipher list e.g. '3DES:+RSA'
	    #
	    # returns: 1 if any	cipher could be	selected and 0 on complete failure

	   The format of $str is described in
	   <http://www.openssl.org/docs/apps/ciphers.html>

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_cipher_list.html>

       o   CTX_set_client_CA_list

	   Sets	the list of CAs	sent to	the client when	requesting a client
	   certificate for $ctx.

	    Net::SSLeay::CTX_set_client_CA_list($ctx, $list);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $list - value corresponding to openssl's X509_NAME_STACK structure
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_client_CA_list.html>

       o   CTX_set_default_passwd_cb

	   Sets	the default password callback called when loading/storing a
	   PEM certificate with	encryption.

	    Net::SSLeay::CTX_set_default_passwd_cb($ctx, $func);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $func - perl reference to	callback function
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_default_passwd_cb.html>

       o   CTX_set_default_passwd_cb_userdata

	   Sets	a pointer to userdata which will be provided to	the password
	   callback on invocation.

	    Net::SSLeay::CTX_set_default_passwd_cb_userdata($ctx, $userdata);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $userdata	- data that will be passed to callback function	when invoked
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_default_passwd_cb.html>

       o   CTX_set_default_verify_paths

	   ??? (more info needed)

	    my $rv = Net::SSLeay::CTX_set_default_verify_paths($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: 1 on success, 0 on failure

       o   CTX_set_ex_data

	   Is used to store application	data at	$data for $idx into the	$ctx
	   object.

	    my $rv = Net::SSLeay::CTX_set_ex_data($ssl,	$idx, $data);
	    # $ssl - value corresponding to openssl's SSL_CTX structure
	    # $idx - (integer) ???
	    # $data - (pointer)	???
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_get_ex_new_index.html>

       o   CTX_set_purpose

	    my $rv = Net::SSLeay::CTX_set_purpose($s, $purpose);
	    # $s - value corresponding to openssl's SSL_CTX structure
	    # $purpose - (integer) purpose identifier
	    #
	    # returns: 1 on success, 0 on failure

	    #avainable purpose identifier
	    1 -	X509_PURPOSE_SSL_CLIENT
	    2 -	X509_PURPOSE_SSL_SERVER
	    3 -	X509_PURPOSE_NS_SSL_SERVER
	    4 -	X509_PURPOSE_SMIME_SIGN
	    5 -	X509_PURPOSE_SMIME_ENCRYPT
	    6 -	X509_PURPOSE_CRL_SIGN
	    7 -	X509_PURPOSE_ANY
	    8 -	X509_PURPOSE_OCSP_HELPER
	    9 -	X509_PURPOSE_TIMESTAMP_SIGN

	    #or	use corresponding constants
	    $purpose = &Net::SSLeay::X509_PURPOSE_SSL_CLIENT;
	    ...
	    $purpose = &Net::SSLeay::X509_PURPOSE_TIMESTAMP_SIGN;

       o   CTX_set_quiet_shutdown

	   Sets	the 'quiet shutdown' flag for $ctx to be mode. SSL objects
	   created from	$ctx inherit the mode valid at the time
	   "Net::SSLeay::new($ctx)" is called.

	    Net::SSLeay::CTX_set_quiet_shutdown($ctx, $mode);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $mode - 0	or 1
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_quiet_shutdown.html>

       o   CTX_set_read_ahead

	    my $rv = Net::SSLeay::CTX_set_read_ahead($ctx, $val);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $val - read_ahead	value to be set
	    #
	    # returns: the original read_ahead value

       o   CTX_set_session_id_context

	   Sets	the context $sid_ctx of	length $sid_ctx_len within which a
	   session can be reused for the $ctx object.

	    my $rv = Net::SSLeay::CTX_set_session_id_context($ctx, $sid_ctx, $sid_ctx_len);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $sid_ctx - data buffer
	    # $sid_ctx_len - length of data in $sid_ctx
	    #
	    # returns: 1 on success, 0 on failure (the error is	logged to the error stack)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_session_id_context.html>

       o   CTX_set_ssl_version

	   Sets	a new default TLS/SSL method for SSL objects newly created
	   from	this $ctx.  SSL	objects	already	created	with
	   "Net::SSLeay::new($ctx)" are	not affected, except when
	   "Net::SSLeay:clear($ssl)" is	being called.

	    my $rv = Net::SSLeay::CTX_set_ssl_version($ctx, $meth);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $meth - value corresponding to openssl's SSL_METHOD structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_ssl_version.html>

       o   CTX_set_timeout

	   Sets	the timeout for	newly created sessions for $ctx	to $t. The
	   timeout value $t must be given in seconds.

	    my $rv = Net::SSLeay::CTX_set_timeout($ctx,	$t);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $t - timeout in seconds
	    #
	    # returns: previously set timeout value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_timeout.html>

       o   CTX_set_tmp_dh

	   Sets	DH parameters to be used to be $dh. The	key is inherited by
	   all ssl objects created from	$ctx.

	    my $rv = Net::SSLeay::CTX_set_tmp_dh($ctx, $dh);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $dh - value corresponding	to openssl's DH	structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_tmp_dh_callback.html>

       o   CTX_set_tmp_dh_callback

	   Sets	the callback function for $ctx to be used when a DH parameters
	   are required	to $tmp_dh_callback.

	    Net::SSLeay::CTX_set_tmp_dh_callback($ctx, $tmp_dh_callback);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # tmp_dh_callback -	(function pointer) ???
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_tmp_dh_callback.html>

       o   CTX_set_tmp_rsa

	   Sets	the temporary/ephemeral	RSA key	to be used to be $rsa.

	    my $rv = Net::SSLeay::CTX_set_tmp_rsa($ctx,	$rsa);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $rsa - value corresponding to openssl's RSA structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_tmp_rsa_callback.html>

	   Not available with OpenSSL 1.1 and later.

       o   CTX_set_tmp_rsa_callback

	   Sets	the callback function for ctx to be used when a
	   temporary/ephemeral RSA key is required to $tmp_rsa_callback.

	   ??? (does this function really work?)

	    Net::SSLeay::CTX_set_tmp_rsa_callback($ctx,	$tmp_rsa_callback);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $tmp_rsa_callback	- (function pointer) ???
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_tmp_rsa_callback.html>

	   Not available with OpenSSL 1.1 and later.

       o   CTX_set_trust

	    my $rv = Net::SSLeay::CTX_set_trust($s, $trust);
	    # $s - value corresponding to openssl's SSL_CTX structure
	    # $trust - (integer) trust identifier
	    #
	    # returns: the original value

	    #available trust identifiers
	    1 -	X509_TRUST_COMPAT
	    2 -	X509_TRUST_SSL_CLIENT
	    3 -	X509_TRUST_SSL_SERVER
	    4 -	X509_TRUST_EMAIL
	    5 -	X509_TRUST_OBJECT_SIGN
	    6 -	X509_TRUST_OCSP_SIGN
	    7 -	X509_TRUST_OCSP_REQUEST
	    8 -	X509_TRUST_TSA

	    #or	use corresponding constants
	    $trust = &Net::SSLeay::X509_TRUST_COMPAT;
	    ...
	    $trust = &Net::SSLeay::X509_TRUST_TSA;

       o   CTX_set_verify_depth

	   Sets	the maximum depth for the certificate chain verification that
	   shall be allowed for	ctx.

	    Net::SSLeay::CTX_set_verify_depth($ctx, $depth);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $depth - max. depth
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_verify.html>

       o   CTX_use_PKCS12_file

	   Adds	the certificate	and private key	from PKCS12 file $p12filename
	   to $ctx.

	    my $rv = Net::SSLeay::CTX_use_PKCS12_file($ctx, $p12filename, $password);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $p12filename - (string) filename
	    # $password	- (string) password to decrypt private key
	    #
	    # returns: 1 on success, 0 on failure

       o   CTX_use_PrivateKey

	   Adds	the private key	$pkey to $ctx.

	    my $rv = Net::SSLeay::CTX_use_PrivateKey($ctx, $pkey);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $pkey - value corresponding to openssl's EVP_PKEY	structure
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   CTX_use_PrivateKey_file

	   Adds	the first private key found in $file to	$ctx.

	    my $rv = Net::SSLeay::CTX_use_PrivateKey_file($ctx,	$file, $type);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $file - (string) file name
	    # $type - (integer)	type - use constants &Net::SSLeay::FILETYPE_PEM	or &Net::SSLeay::FILETYPE_ASN1
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   CTX_use_RSAPrivateKey

	   Adds	the RSA	private	key $rsa to $ctx.

	    my $rv = Net::SSLeay::CTX_use_RSAPrivateKey($ctx, $rsa);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $rsa - value corresponding to openssl's RSA structure
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   CTX_use_RSAPrivateKey_file

	   Adds	the first RSA private key found	in $file to $ctx.

	    my $rv = Net::SSLeay::CTX_use_RSAPrivateKey_file($ctx, $file, $type);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $file - (string) file name
	    # $type - (integer)	type - use constants &Net::SSLeay::FILETYPE_PEM	or &Net::SSLeay::FILETYPE_ASN1
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

       o   CTX_use_certificate

	   Loads the certificate $x into $ctx

	    my $rv = Net::SSLeay::CTX_use_certificate($ctx, $x);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   CTX_use_certificate_chain_file

	   Loads a certificate chain from $file	into $ctx. The certificates
	   must	be in PEM format and must be sorted starting with the
	   subject's certificate (actual client	or server certificate),
	   followed by intermediate CA certificates if applicable, and ending
	   at the highest level	(root) CA.

	    my $rv = Net::SSLeay::CTX_use_certificate_chain_file($ctx, $file);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $file - (string) file name
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   CTX_use_certificate_file

	   Loads the first certificate stored in $file into $ctx.

	    my $rv = Net::SSLeay::CTX_use_certificate_file($ctx, $file,	$type);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $file - (string) file name
	    # $type - (integer)	type - use constants &Net::SSLeay::FILETYPE_PEM	or &Net::SSLeay::FILETYPE_ASN1
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       Low level API: SSL_* related functions

       NOTE: Please note that the function described in	this chapter have
       "SSL_" part stripped from their original	openssl	names.

       o   new

	   Creates a new SSL structure which is	needed to hold the data	for a
	   TLS/SSL connection.	The new	structure inherits the settings	of the
	   underlying context $ctx: connection method (SSLv2/v3/TLSv1),
	   options, verification settings, timeout settings.

	    my $rv = Net::SSLeay::new($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: value corresponding to openssl's	SSL structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_new.html>

       o   accept

	   Waits for a TLS/SSL client to initiate the TLS/SSL handshake. The
	   communication channel must already have been	set and	assigned to
	   the ssl by setting an underlying BIO.

	    my $rv = Net::SSLeay::accept($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 1 = success, 0 =	handshake not successful, <0 = fatal error during handshake

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_accept.html>

       o   add_client_CA

	   Adds	the CA name extracted from cacert to the list of CAs sent to
	   the client when requesting a	client certificate for the chosen ssl,
	   overriding the setting valid	for ssl's SSL_CTX object.

	    my $rv = Net::SSLeay::add_client_CA($ssl, $x);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_client_CA_list.html>

       o   callback_ctrl

	   ??? (more info needed)

	    my $rv = Net::SSLeay::callback_ctrl($ssl, $cmd, $fp);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $cmd - (integer) command id
	    # $fp - (function pointer) ???
	    #
	    # returns: ???

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_ctrl.html>

       o   check_private_key

	   Checks the consistency of a private key with	the corresponding
	   certificate loaded into $ssl

	    my $rv = Net::SSLeay::check_private_key($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   clear

	   Reset SSL object to allow another connection.

	    Net::SSLeay::clear($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_clear.html>

       o   connect

	   Initiate the	TLS/SSL	handshake with an TLS/SSL server.

	    my $rv = Net::SSLeay::connect($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 1 = success, 0 =	handshake not successful, <0 = fatal error during handshake

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_connect.html>

       o   copy_session_id

	   Copies the session structure	fro $from to $to (+ also the private
	   key and certificate associated with $from).

	    Net::SSLeay::copy_session_id($to, $from);
	    # $to - value corresponding	to openssl's SSL structure
	    # $from - value corresponding to openssl's SSL structure
	    #
	    # returns: no return value

       o   ctrl

	   Internal handling function for SSL objects.

	   BEWARE: openssl doc says: This function should never	be called
	   directly!

	    my $rv = Net::SSLeay::ctrl($ssl, $cmd, $larg, $parg);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $cmd - (integer) command id
	    # $larg - (integer)	long ???
	    # $parg - (string/pointer) ???
	    #
	    # returns: (long) result of	given command ???

	   For more details about valid	$cmd values check "CTX_ctrl".

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_ctrl.html>

       o   do_handshake

	   Will	wait for a SSL/TLS handshake to	take place. If the connection
	   is in client	mode, the handshake will be started. The handshake
	   routines may	have to	be explicitly set in advance using either
	   SSL_set_connect_state or SSL_set_accept_state(3).

	    my $rv = Net::SSLeay::do_handshake($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 1 = success, 0 =	handshake not successful, <0 = fatal error during handshake

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_do_handshake.html>

       o   dup

	   Returns a duplicate of $ssl.

	    my $rv = Net::SSLeay::dup($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's	SSL structure (0 on failure)

       o   free

	   Free	an allocated SSL structure.

	    Net::SSLeay::free($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_free.html>

       o   get_SSL_CTX

	   Returns a pointer to	the SSL_CTX object, from which $ssl was
	   created with	Net::SSLeay::new.

	    my $rv = Net::SSLeay::get_SSL_CTX($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's	SSL_CTX	structure (0 on	failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_SSL_CTX.html>

       o   set_SSL_CTX

	   Sets	the SSL_CTX the	corresponds to an SSL session.

	    my $the_ssl_ctx = Net::SSLeay::set_SSL_CTX($ssl, $ssl_ctx);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $ssl_ctx - Change	the ssl	object to the given ssl_ctx
	    #
	    # returns -	the ssl_ctx

       o   get_app_data

	   Can be used to get application defined value/data.

	    my $rv = Net::SSLeay::get_app_data($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: string/buffer/pointer ???

       o   set_app_data

	   Can be used to set some application defined value/data.

	    my $rv = Net::SSLeay::set_app_data($ssl, $arg);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $arg - (string/buffer/pointer ???) data
	    #
	    # returns: ???

       o   get_certificate

	   Gets	X509 certificate from an established SSL connection.

	    my $rv = Net::SSLeay::get_certificate($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's	X509 structure (0 on failure)

       o   get_cipher

	   Obtains the name of the currently used cipher.

	    my $rv = Net::SSLeay::get_cipher($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (string)	cipher name e.g. 'DHE-RSA-AES256-SHA' or '', when no session has been established.

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_current_cipher.html>

       o   get_cipher_bits

	   Obtain the number of	secret/algorithm bits used.

	    my $rv = Net::SSLeay::get_cipher_bits($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: number of secret	bits used by current cipher

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_current_cipher.html> and
	   <http://www.openssl.org/docs/ssl/SSL_CIPHER_get_name.html>

       o   get_cipher_list

	   Returns the name (string) of	the SSL_CIPHER listed for $ssl with
	   priority $n.

	    my $rv = Net::SSLeay::get_cipher_list($ssl,	$n);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $n - (integer) priority
	    #
	    # returns: (string)	cipher name e.g. 'EDH-DSS-DES-CBC3-SHA'	or '' in case of error

	   Call	Net::SSLeay::get_cipher_list with priority starting from 0 to
	   obtain the sorted list of available ciphers,	until '' is returned:

	    my $priority = 0;
	    while (my $c = Net::SSLeay::get_cipher_list($ssl, $priority)) {
	      print "cipher[$priority] = $c\n";
	      $priority++;
	    }

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_ciphers.html>

       o   get_client_CA_list

	   Returns the list of client CAs explicitly set for $ssl using
	   "Net::SSleay::set_client_CA_list" or	$ssl's SSL_CTX object with
	   "Net::SSLeay::CTX_set_client_CA_list", when in server mode.

	   In client mode, returns the list of client CAs sent from the
	   server, if any.

	    my $rv = Net::SSLeay::get_client_CA_list($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's	STACK_OF(X509_NAME) structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_client_CA_list.html>

       o   get_current_cipher

	   Returns the cipher actually used.

	    my $rv = Net::SSLeay::get_current_cipher($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's	SSL_CIPHER structure (0	on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_current_cipher.html>

       o   get_default_timeout

	   Returns the default timeout value assigned to SSL_SESSION objects
	   negotiated for the protocol valid for $ssl.

	    my $rv = Net::SSLeay::get_default_timeout($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (long) timeout in seconds

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_default_timeout.html>

       o   get_error

	   Returns a result code for a preceding call to "connect", "accept",
	   "do_handshake", "read", "peek" or "write" on	$ssl.

	    my $rv = Net::SSLeay::get_error($ssl, $ret);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $ret - return value of preceding TLS/SSL I/O operation
	    #
	    # returns: result code, which is one of the	following values:
	    #  0 - SSL_ERROR_NONE
	    #  1 - SSL_ERROR_SSL
	    #  2 - SSL_ERROR_WANT_READ
	    #  3 - SSL_ERROR_WANT_WRITE
	    #  4 - SSL_ERROR_WANT_X509_LOOKUP
	    #  5 - SSL_ERROR_SYSCALL
	    #  6 - SSL_ERROR_ZERO_RETURN
	    #  7 - SSL_ERROR_WANT_CONNECT
	    #  8 - SSL_ERROR_WANT_ACCEPT

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_error.html>

       o   get_ex_data

	   Is used to retrieve the information for $idx	from $ssl.

	    my $rv = Net::SSLeay::get_ex_data($ssl, $idx);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $idx - (integer) index for application specific data
	    #
	    # returns: pointer to ???

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_ex_new_index.html>

       o   set_ex_data

	   Is used to store application	data at	$data for $idx into the	$ssl
	   object.

	    my $rv = Net::SSLeay::set_ex_data($ssl, $idx, $data);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $idx - (integer) ???
	    # $data - (pointer)	???
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_ex_new_index.html>

       o   get_ex_new_index

	   Is used to register a new index for application specific data.

	    my $rv = Net::SSLeay::get_ex_new_index($argl, $argp, $new_func, $dup_func, $free_func);
	    # $argl - (long) ???
	    # $argp - (pointer)	???
	    # $new_func	- function pointer ??? (CRYPTO_EX_new *)
	    # $dup_func	- function pointer ??? (CRYPTO_EX_dup *)
	    # $free_func - function pointer ???	(CRYPTO_EX_free	*)
	    #
	    # returns: (integer) ???

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_ex_new_index.html>

       o   get_fd

	   Returns the file descriptor which is	linked to $ssl.

	    my $rv = Net::SSLeay::get_fd($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: file descriptor (>=0) or	-1 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_fd.html>

       o   get_finished

	   Obtains the latest 'Finished' message sent to the peer.

	   ??? (does this function really work?)

	    my $rv = Net::SSLeay::get_finished($ssl, $buf, $count);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $buf - buffer where the returned data will be stored (pointer ???, pre-allocated ???)
	    # $count - max. size of return data
	    #
	    # returns: actual size of the returned data	in $buf

       o   get_peer_finished

	   Obtains the latest 'Finished' message expected from the peer.

	   ??? (does this function really work?)

	    my $rv = Net::SSLeay::get_peer_finished($ssl, $buf,	$count);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $buf - buffer where the returned data will be stored (pointer ???, pre-allocated ???)
	    # $count - max. size of the	return data
	    #
	    # returns: actual size of the returned data	in $buf

       o   get_keyblock_size

	   Gets	the length of the TLS keyblock.

	   NOTE: Does not exactly correspond to	any low	level API function.

	    my $rv = Net::SSLeay::get_keyblock_size($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: keyblock	size, -1 on error

       o   get_mode

	   Returns the mode (bitmask) set for $ssl.

	    my $rv = Net::SSLeay::get_mode($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: mode (bitmask)

	   To decode the return	value (bitmask)	see documentation for
	   "CTX_get_mode".

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_mode.html>

       o   set_mode

	   Adds	the mode set via bitmask in $mode to $ssl. Options already set
	   before are not cleared.

	    my $rv = Net::SSLeay::set_mode($ssl, $mode);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $mode - mode (bitmask)
	    #
	    # returns: the new mode bitmask after adding $mode

	   For $mode bitmask details see "CTX_get_mode".

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_mode.html>

       o   get_options

	   Returns the options (bitmask) set for $ssl.

	    my $rv = Net::SSLeay::get_options($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: options (bitmask)

	   To decode the return	value (bitmask)	see documentation for
	   "CTX_get_options".

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_options.html>

       o   set_options

	   Adds	the options set	via bitmask in $options	to $ssl. Options
	   already set before are not cleared!

	    Net::SSLeay::set_options($ssl, $options);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $options - options (bitmask)
	    #
	    # returns: the new options bitmask after adding $options

	   For $options	bitmask	details	see "CTX_get_options".

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_options.html>

       o   get_peer_certificate

	   Get the X509	certificate of the peer.

	    my $rv = Net::SSLeay::get_peer_certificate($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's	X509 structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_peer_certificate.html>

       o   get_peer_cert_chain

	   Get the certificate chain of	the peer as an array of	X509
	   structures.

	    my @rv = Net::SSLeay::get_peer_cert_chain($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: list of X509 structures

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_peer_certificate.html>

       o   get_quiet_shutdown

	   Returns the 'quiet shutdown'	setting	of ssl.

	    my $rv = Net::SSLeay::get_quiet_shutdown($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (integer) current 'quiet	shutdown' value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_quiet_shutdown.html>

       o   get_rbio

	   Get 'read' BIO linked to an SSL object $ssl.

	    my $rv = Net::SSLeay::get_rbio($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's	BIO structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_rbio.html>

       o   get_read_ahead

	    my $rv = Net::SSLeay::get_read_ahead($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (integer) read_ahead value

       o   set_read_ahead

	    Net::SSLeay::set_read_ahead($ssl, $val);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $val - read_ahead	value to be set
	    #
	    # returns: the original read_ahead value

       o   get_server_random

	   Returns internal SSLv3 server_random	value.

	    Net::SSLeay::get_server_random($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: server_random value (binary data)

       o   get_client_random

	   NOTE: Does not exactly correspond to	any low	level API function

	   Returns internal SSLv3 client_random	value.

	    Net::SSLeay::get_client_random($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: client_random value (binary data)

       o   export_keying_material

	   Returns a buffer of $req_len	bytes of keying	material based on the
	   constant string $label using	the masterkey and client and server
	   random strings as described in draft-ietf-pppext-eap-ttls-01.txt
	   and See rfc2716 If p	is present, it will be concatenated before
	   generating the keying material Returns undef	on error

	       my $out = Net::SSLeay::export_keying_material($ssl, $req_len, $label, $p);

       o   get_session

	   Retrieve TLS/SSL session data used in $ssl. The reference count of
	   the SSL_SESSION is NOT incremented.

	    my $rv = Net::SSLeay::get_session($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's	SSL_SESSION structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_session.html>

       o   SSL_get0_session

	   The alias for "get_session" (note that the name is
	   "SSL_get0_session" NOT "get0_session").

	    my $rv = Net::SSLeay::SSL_get0_session();

       o   get1_session

	   Returns a pointer to	the SSL_SESSION	actually used in $ssl. The
	   reference count of the SSL_SESSION is incremented by	1.

	    my $rv = Net::SSLeay::get1_session($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's	SSL_SESSION structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_session.html>

       o   get_shared_ciphers

	   Returns string with a list (colon ':' separated) of ciphers shared
	   between client and server within SSL	session	$ssl.

	    my $rv = Net::SSLeay::get_shared_ciphers()
	    #
	    # returns: string like 'ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES256-SHA:DHE-DSS-AES256-SHA:...'

       o   get_shutdown

	   Returns the shutdown	mode of	$ssl.

	    my $rv = Net::SSLeay::get_shutdown($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: shutdown	mode (bitmask) of ssl

	    #to	decode the return value	(bitmask) use:
	    0 -	No shutdown setting, yet
	    1 -	SSL_SENT_SHUTDOWN
	    2 -	SSL_RECEIVED_SHUTDOWN

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_set_shutdown.html>

       o   get_ssl_method

	   Returns a function pointer to the TLS/SSL method set	in $ssl.

	    my $rv = Net::SSLeay::get_ssl_method($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's	SSL_METHOD structure (0	on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_ssl_version.html>

       o   get_state

	   Returns the SSL connection state.

	    my $rv = Net::SSLeay::get_state($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (integer) state value
	    #	       to decode the returned state check:
	    #	       SSL_ST_*	constants in openssl/ssl.h
	    #	       SSL2_ST_* constants in openssl/ssl2.h
	    #	       SSL23_ST_* constants in openssl/ssl23.h
	    #	       SSL3_ST_* + DTLS1_ST_* constants	in openssl/ssl3.h

       o   state

	   Exactly the same as "get_state".

	    my $rv = Net::SSLeay::state($ssl);

       o   set_state

	   Sets	the SSL	connection state.

	    Net::SSLeay::set_state($ssl,Net::SSLeay::SSL_ST_ACCEPT());

	   Not available with OpenSSL 1.1 and later.

       o   get_verify_depth

	   Returns the verification depth limit	currently set in $ssl.

	    my $rv = Net::SSLeay::get_verify_depth($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: current depth or	-1 if no limit has been	explicitly set

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_get_verify_mode.html>

       o   set_verify_depth

	   Sets	the maximum depth for the certificate chain verification that
	   shall be allowed for	$ssl.

	    Net::SSLeay::set_verify_depth($ssl,	$depth);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $depth - (integer) depth
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_verify.html>

       o   get_verify_mode

	   Returns the verification mode (bitmask) currently set in $ssl.

	    my $rv = Net::SSLeay::get_verify_mode($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: mode (bitmask)

	   To decode the return	value (bitmask)	see documentation for
	   "CTX_get_verify_mode".

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_get_verify_mode.html>

       o   set_verify

	   Sets	the verification flags for $ssl	to be $mode and	specifies the
	   $verify_callback function to	be used.

	    Net::SSLeay::set_verify($ssl, $mode, $callback);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $mode - mode (bitmask)
	    # $callback	- [optional] reference to perl callback	function
	    #
	    # returns: no return value

	   For $mode bitmask details see "CTX_get_verify_mode".

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_verify.html>

       o   get_verify_result

	   Returns the result of the verification of the X509 certificate
	   presented by	the peer, if any.

	    my $rv = Net::SSLeay::get_verify_result($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (integer)
	    #	   0 - X509_V_OK: ok
	    #	   2 - X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT: unable to get issuer certificate
	    #	   3 - X509_V_ERR_UNABLE_TO_GET_CRL: unable to get certificate CRL
	    #	   4 - X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE: unable to decrypt certificate's signature
	    #	   5 - X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE: unable to decrypt CRL's signature
	    #	   6 - X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY: unable to	decode issuer public key
	    #	   7 - X509_V_ERR_CERT_SIGNATURE_FAILURE: certificate signature	failure
	    #	   8 - X509_V_ERR_CRL_SIGNATURE_FAILURE: CRL signature failure
	    #	   9 - X509_V_ERR_CERT_NOT_YET_VALID: certificate is not yet valid
	    #	  10 - X509_V_ERR_CERT_HAS_EXPIRED: certificate	has expired
	    #	  11 - X509_V_ERR_CRL_NOT_YET_VALID: CRL is not	yet valid
	    #	  12 - X509_V_ERR_CRL_HAS_EXPIRED: CRL has expired
	    #	  13 - X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD: format error in certificate's	notBefore field
	    #	  14 - X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD: format	error in certificate's notAfter	field
	    #	  15 - X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD: format error in CRL's	lastUpdate field
	    #	  16 - X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD: format error in CRL's	nextUpdate field
	    #	  17 - X509_V_ERR_OUT_OF_MEM: out of memory
	    #	  18 - X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT: self signed certificate
	    #	  19 - X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN: self signed certificate in	certificate chain
	    #	  20 - X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY: unable to get local issuer	certificate
	    #	  21 - X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE: unable to verify the	first certificate
	    #	  22 - X509_V_ERR_CERT_CHAIN_TOO_LONG: certificate chain too long
	    #	  23 - X509_V_ERR_CERT_REVOKED:	certificate revoked
	    #	  24 - X509_V_ERR_INVALID_CA: invalid CA certificate
	    #	  25 - X509_V_ERR_PATH_LENGTH_EXCEEDED:	path length constraint exceeded
	    #	  26 - X509_V_ERR_INVALID_PURPOSE: unsupported certificate purpose
	    #	  27 - X509_V_ERR_CERT_UNTRUSTED: certificate not trusted
	    #	  28 - X509_V_ERR_CERT_REJECTED: certificate rejected
	    #	  29 - X509_V_ERR_SUBJECT_ISSUER_MISMATCH: subject issuer mismatch
	    #	  30 - X509_V_ERR_AKID_SKID_MISMATCH: authority	and subject key	identifier mismatch
	    #	  31 - X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH: authority and issuer serial number mismatch
	    #	  32 - X509_V_ERR_KEYUSAGE_NO_CERTSIGN:key usage does not include certificate signing
	    #	  50 - X509_V_ERR_APPLICATION_VERIFICATION: application	verification failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_verify_result.html>

       o   set_verify_result

	   Override result of peer certificate verification.

	    Net::SSLeay::set_verify_result($ssl, $v);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $v - (integer) result value
	    #
	    # returns: no return value

	   For more info about valid return values see "get_verify_result"

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_set_verify_result.html>

       o   get_wbio

	   Get 'write' BIO linked to an	SSL object $ssl.

	    my $rv = Net::SSLeay::get_wbio($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's	BIO structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_get_rbio.html>

       o   load_client_CA_file

	   Load	X509 certificates from file (PEM formatted).

	    my $rv = Net::SSLeay::load_client_CA_file($file);
	    # $file - (string) file name
	    #
	    # returns: value corresponding to openssl's	STACK_OF(X509_NAME) structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_load_client_CA_file.html>

       o   clear_num_renegotiations

	   Executes SSL_CTRL_CLEAR_NUM_RENEGOTIATIONS command on $ssl.

	    my $rv = Net::SSLeay::clear_num_renegotiations($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: command result

       o   need_tmp_RSA

	   Executes SSL_CTRL_NEED_TMP_RSA command on $ssl.

	    my $rv = Net::SSLeay::need_tmp_RSA($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: command result

	   Not available with OpenSSL 1.1 and later.

       o   num_renegotiations

	   Executes SSL_CTRL_GET_NUM_RENEGOTIATIONS command on $ssl.

	    my $rv = Net::SSLeay::num_renegotiations($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: command result

       o   total_renegotiations

	   Executes SSL_CTRL_GET_TOTAL_RENEGOTIATIONS command on $ssl.

	    my $rv = Net::SSLeay::total_renegotiations($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: command result

       o   peek

	   Copies $max bytes from the specified	$ssl into the returned value.
	   In contrast to the "Net::SSLeay::read()" function, the data in the
	   SSL buffer is unmodified after the SSL_peek() operation.

	    Net::SSLeay::peek($ssl, $max);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $max - [optional]	max bytes to peek (integer) - default is 32768
	    #
	    # in scalar	context: data read from	the TLS/SSL connection,	undef on error
	    # in list context:	 two-item array	consisting of data read	(undef on error),
	    #			   and return code from	SSL_read().

       o   pending

	   Obtain number of readable bytes buffered in $ssl object.

	    my $rv = Net::SSLeay::pending($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: the number of bytes pending

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_pending.html>

       o   read

	   Tries to read $max bytes from the specified $ssl.

	    my $got = Net::SSLeay::read($ssl, $max);
	    my($got, $rv) = Net::SSLeay::read($ssl, $max);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $max - [optional]	max bytes to read (integer) - default is 32768
	    #
	    # returns:
	    # in scalar	context: data read from	the TLS/SSL connection,	undef on error
	    # in list context:	 two-item array	consisting of data read	(undef on error),
	    #			   and return code from	SSL_read().

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_read.html>

       o   renegotiate

	   Turn	on flags for renegotiation so that renegotiation will happen

	    my $rv = Net::SSLeay::renegotiate($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 1 on success, 0 on failure

       o   rstate_string

	   Returns a 2 letter string indicating	the current read state of the
	   SSL object $ssl.

	    my $rv = Net::SSLeay::rstate_string($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 2-letter	string

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_rstate_string.html>

       o   rstate_string_long

	   Returns a string indicating the current read	state of the SSL
	   object ssl.

	    my $rv = Net::SSLeay::rstate_string_long($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: string with current state

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_rstate_string.html>

       o   session_reused

	   Query whether a reused session was negotiated during	handshake.

	    my $rv = Net::SSLeay::session_reused($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 0 - new session was negotiated; 1 - session was reused.

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_session_reused.html>

       o   set1_param

	   Applies X509	verification parameters	$vpm on	$ssl

	    my $rv = Net::SSLeay::set1_param($ssl, $vpm);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $vpm - value corresponding to openssl's X509_VERIFY_PARAM	structure
	    #
	    # returns: 1 on success, 0 on failure

       o   set_accept_state

	   Sets	$ssl to	work in	server mode.

	    Net::SSLeay::set_accept_state($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_set_connect_state.html>

       o   set_bio

	   Connects the	BIOs $rbio and $wbio for the read and write operations
	   of the TLS/SSL (encrypted) side of $ssl.

	    Net::SSLeay::set_bio($ssl, $rbio, $wbio);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $rbio - value corresponding to openssl's BIO structure
	    # $wbio - value corresponding to openssl's BIO structure
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_set_bio.html>

       o   set_cipher_list

	   Sets	the list of ciphers only for ssl.

	    my $rv = Net::SSLeay::set_cipher_list($ssl,	$str);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $str - (string) cipher list e.g. '3DES:+RSA'
	    #
	    # returns: 1 if any	cipher could be	selected and 0 on complete failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_cipher_list.html>

       o   set_client_CA_list

	   Sets	the list of CAs	sent to	the client when	requesting a client
	   certificate for the chosen $ssl, overriding the setting valid for
	   $ssl's SSL_CTX object.

	    my $rv = Net::SSLeay::set_client_CA_list($ssl, $list);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $list - value corresponding to openssl's STACK_OF(X509_NAME) structure
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_client_CA_list.html>

       o   set_connect_state

	   Sets	$ssl to	work in	client mode.

	    Net::SSLeay::set_connect_state($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_set_connect_state.html>

       o   set_fd

	   Sets	the file descriptor $fd	as the input/output facility for the
	   TLS/SSL (encrypted) side of $ssl, $fd will typically	be the socket
	   file	descriptor of a	network	connection.

	    my $rv = Net::SSLeay::set_fd($ssl, $fd);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $fd - (integer) file handle (got via perl's fileno)
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_set_fd.html>

       o   set_rfd

	   Sets	the file descriptor $fd	as the input (read) facility for the
	   TLS/SSL (encrypted) side of $ssl.

	    my $rv = Net::SSLeay::set_rfd($ssl,	$fd);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $fd - (integer) file handle (got via perl's fileno)
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_set_fd.html>

       o   set_wfd

	    my $rv = Net::SSLeay::set_wfd($ssl,	$fd);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $fd - (integer) file handle (got via perl's fileno)
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_set_fd.html>

       o   set_info_callback

	   Sets	the callback function, that can	be used	to obtain state
	   information for $ssl	during connection setup	and use.  When
	   callback is undef, the callback setting currently valid for ctx is
	   used.

	    Net::SSLeay::set_info_callback($ssl, $cb, [$data]);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $cb - sub	{ my ($ssl,$where,$ret,$data) =	@_; ...	}
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_info_callback.html>

       o   CTX_set_info_callback

	   Sets	the callback function on ctx, that can be used to obtain state
	   information during ssl connection setup and use.  When callback is
	   undef, an existing callback will be disabled.

	    Net::SSLeay::CTX_set_info_callback($ssl, $cb, [$data]);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $cb - sub	{ my ($ssl,$where,$ret,$data) =	@_; ...	}
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_info_callback.html>

       o   set_pref_cipher

	   Sets	the list of available ciphers for $ssl using the control
	   string $str.

	    my $rv = Net::SSLeay::set_pref_cipher($ssl,	$str);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $str - (string) cipher list e.g. '3DES:+RSA'
	    #
	    # returns: 1 if any	cipher could be	selected and 0 on complete failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_cipher_list.html>

       o   set_purpose

	    my $rv = Net::SSLeay::set_purpose($ssl, $purpose);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $purpose - (integer) purpose identifier
	    #
	    # returns: 1 on success, 0 on failure

	   For more info about available $purpose identifiers see
	   "CTX_set_purpose".

       o   set_quiet_shutdown

	   Sets	the 'quiet shutdown' flag for $ssl to be $mode.

	    Net::SSLeay::set_quiet_shutdown($ssl, $mode);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $mode - 0	or 1
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_quiet_shutdown.html>

       o   set_session

	   Set a TLS/SSL session to be used during TLS/SSL connect.

	    my $rv = Net::SSLeay::set_session($to, $ses);
	    # $to - value corresponding	to openssl's SSL structure
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_set_session.html>

       o   set_session_id_context

	   Sets	the context $sid_ctx of	length $sid_ctx_len within which a
	   session can be reused for the $ssl object.

	    my $rv = Net::SSLeay::set_session_id_context($ssl, $sid_ctx, $sid_ctx_len);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $sid_ctx - data buffer
	    # $sid_ctx_len - length of data in $sid_ctx
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_session_id_context.html>

       o   set_session_secret_cb

	   Setup pre-shared secret session resumption function.

	    Net::SSLeay::set_session_secret_cb($ssl, $func, $data);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $func - perl reference to	callback function
	    # $data - [optional] data that will	be passed to callback function when invoked
	    #
	    # returns: no return value

	   The callback	function will be called	like:
	   callback_function($secret, $ciphers,	$pref_cipher, $data);

	   # $secret is	the current master session key,	usually	all 0s at the
	   beginning of	a session # $ciphers is	ref to an array	of peer	cipher
	   names # $pref_cipher	is a ref to an index into the list of cipher
	   names of #  the preferred cipher. Set it if you want	to specify a
	   preferred cipher # $data is the data	passed to
	   set_session_secret_cb

	   The callback	function should	return 1 if it likes the suggested
	   cipher (or has selected an alternative by setting pref_cipher),
	   else	it should return 0 (in which case OpenSSL will select its own
	   preferred cipher).

	   With	OpenSSL	1.1 and	later, callback_function can change the	master
	   key for the session by altering $secret and returning 1.

       o   CTX_set_tlsext_ticket_getkey_cb

	   Setup encryption for	TLS session tickets (stateless session reuse).

	    Net::SSLeay::CTX_set_tlsext_ticket_getkey_cb($ctx, $func, $data);
	    # $ctx  - value corresponding to openssl's SSL_CTX structure
	    # $func - perl reference to	callback function
	    # $data - [optional] data that will	be passed to callback function when invoked
	    #
	    # returns: no return value

	   The callback	function will be called	like:
	   getkey($data,[$key_name]) ->	($key,$current_key_name)

	   # $data is the data passed to set_session_secret_cb # $key_name is
	   the name of the key OpenSSL has extracted from the session ticket #
	   $key	is the requested key for ticket	encryption + HMAC #
	   $current_key_name is	the name for the currently valid key

	   OpenSSL will	call the function without a key	name if	it generates a
	   new ticket.	It then	needs the callback to return the
	   encryption+HMAC key and an identifier (key name) for	this key.

	   When	OpenSSL	gets a session ticket from the client it extracts the
	   key name and	calls the callback with	this name as argument. It then
	   expects the callback	to return the encryption+HMAC key matching the
	   requested key name and and also the key name	which should be	used
	   at the moment. If the requested key name and	the returned key name
	   differ it means that	this session ticket was	created	with an
	   expired key and need	to be renewed. In this case OpenSSL will call
	   the callback	again with no key name to create a new session ticket
	   based on the	old one.

	   The key must	be at least 32 byte of random data which can be
	   created with	RAND_bytes. Internally the first 16 byte are used as
	   key in AES-128 encryption while the next 16 byte are	used for the
	   SHA-256 HMAC.  The key name are binary data and must	be exactly 16
	   byte	long.

	   Example:

	       Net::SSLeay::RAND_bytes(my $oldkey,32);
	       Net::SSLeay::RAND_bytes(my $newkey,32);
	       my $oldkey_name = pack("a16",'oldsecret');
	       my $newkey_name = pack("a16",'newsecret');

	       my @keys	= (
		   [ $newkey_name, $newkey ], #	current	active key
		   [ $oldkey_name, $oldkey ], #	already	expired
	       );

	       Net::SSLeay::CTX_set_tlsext_ticket_getkey_cb($server2->_ctx, sub	{
		   my ($mykeys,$name) =	@_;

		   # return (current_key, current_key_name) if no name given
		   return ($mykeys->[0][1],$mykeys->[0][0]) if ! $name;

		   # return (matching_key, current_key_name) if	we find	a key matching
		   # the given name
		   for(my $i = 0; $i<@$mykeys; $i++) {
		       next if $name ne	$mykeys->[$i][0];
		       return ($mykeys->[$i][1],$mykeys->[0][0]);
		   }

		   # no	matching key found
		   return;
	       },\@keys);

	   This	function is based on the OpenSSL function
	   SSL_CTX_set_tlsext_ticket_key_cb but	provides a simpler to use
	   interface. For more information see
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_tlsext_ticket_key_cb.html>

       o   set_shutdown

	   Sets	the shutdown state of $ssl to $mode.

	    Net::SSLeay::set_shutdown($ssl, $mode);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $mode - (integer)	shutdown mode:
	    #	      0	- No shutdown
	    #	      1	- SSL_SENT_SHUTDOWN
	    #	      2	- SSL_RECEIVED_SHUTDOWN
	    #	      3	- SSL_RECEIVED_SHUTDOWN+SSL_SENT_SHUTDOWN
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_set_shutdown.html>

       o   set_ssl_method

	   Sets	a new TLS/SSL method for a particular $ssl object.

	    my $rv = Net::SSLeay::set_ssl_method($ssl, $method);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $method -	value corresponding to openssl's SSL_METHOD structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_ssl_version.html>

       o   set_tmp_dh

	   Sets	DH parameters to be used to be $dh.

	    my $rv = Net::SSLeay::set_tmp_dh($ssl, $dh);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $dh - value corresponding	to openssl's DH	structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_tmp_dh_callback.html>

       o   set_tmp_dh_callback

	   Sets	the callback function for $ssl to be used when a DH parameters
	   are required	to $dh_cb.

	   ??? (does this function really work?)

	    Net::SSLeay::set_tmp_dh_callback($ssl, $dh);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $dh_cb - pointer to function ???
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_tmp_dh_callback.html>

       o   set_tmp_rsa

	   Sets	the temporary/ephemeral	RSA key	to be used in $ssl to be $rsa.

	    my $rv = Net::SSLeay::set_tmp_rsa($ssl, $rsa);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $rsa - value corresponding to openssl's RSA structure
	    #
	    # returns: 1 on success, 0 on failure

	   Example:

	    $rsakey = Net::SSLeay::RSA_generate_key();
	    Net::SSLeay::set_tmp_rsa($ssl, $rsakey);
	    Net::SSLeay::RSA_free($rsakey);

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_tmp_rsa_callback.html>

       o   set_tmp_rsa_callback

	   Sets	the callback function for $ssl to be used when a
	   temporary/ephemeral RSA key is required to $tmp_rsa_callback.

	   ??? (does this function really work?)

	    Net::SSLeay::set_tmp_rsa_callback($ssl, $tmp_rsa_callback);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $tmp_rsa_callback	- (function pointer) ???
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_tmp_rsa_callback.html>

       o   set_trust

	    my $rv = Net::SSLeay::set_trust($ssl, $trust);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $trust - (integer) trust identifier
	    #
	    # returns: the original value

	   For more details about $trust values	see "CTX_set_trust".

       o   shutdown

	   Shuts down an active	TLS/SSL	connection. It sends the 'close
	   notify' shutdown alert to the peer.

	    my $rv = Net::SSLeay::shutdown($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 1 - shutdown was	successfully completed
	    #	       0 - shutdown is not yet finished,
	    #	      -1 - shutdown was	not successful

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_shutdown.html>

       o   state_string

	   Returns a 6 letter string indicating	the current state of the SSL
	   object $ssl.

	    my $rv = Net::SSLeay::state_string($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 6-letter	string

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_state_string.html>

       o   state_string_long

	   Returns a string indicating the current state of the	SSL object
	   $ssl.

	    my $rv = Net::SSLeay::state_string_long($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: state strings

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_state_string.html>

       o   use_PrivateKey

	   Adds	$pkey as private key to	$ssl.

	    my $rv = Net::SSLeay::use_PrivateKey($ssl, $pkey);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $pkey - value corresponding to openssl's EVP_PKEY	structure
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   use_PrivateKey_ASN1

	   Adds	the private key	of type	$pk stored in $data to $ssl.

	    my $rv = Net::SSLeay::use_PrivateKey_ASN1($pk, $ssl, $d, $len);
	    # $pk - (integer) key type,	NID of corresponding algorithm
	    # $ssl - value corresponding to openssl's SSL structure
	    # $data - key data (binary)
	    # $len - length of $data
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   use_PrivateKey_file

	   Adds	the first private key found in $file to	$ssl.

	    my $rv = Net::SSLeay::use_PrivateKey_file($ssl, $file, $type);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $file - (string) file name
	    # $type - (integer)	type - use constants &Net::SSLeay::FILETYPE_PEM	or &Net::SSLeay::FILETYPE_ASN1
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   use_RSAPrivateKey

	   Adds	$rsa as	RSA private key	to $ssl.

	    my $rv = Net::SSLeay::use_RSAPrivateKey($ssl, $rsa);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $rsa - value corresponding to openssl's RSA structure
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   use_RSAPrivateKey_ASN1

	   Adds	RSA private key	stored in $data	to $ssl.

	    my $rv = Net::SSLeay::use_RSAPrivateKey_ASN1($ssl, $data, $len);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $data - key data (binary)
	    # $len - length of $data
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   use_RSAPrivateKey_file

	   Adds	the first RSA private key found	in $file to $ssl.

	    my $rv = Net::SSLeay::use_RSAPrivateKey_file($ssl, $file, $type);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $file - (string) file name
	    # $type - (integer)	type - use constants &Net::SSLeay::FILETYPE_PEM	or &Net::SSLeay::FILETYPE_ASN1
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   use_certificate

	   Loads the certificate $x into $ssl.

	    my $rv = Net::SSLeay::use_certificate($ssl,	$x);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   use_certificate_ASN1

	   Loads the ASN1 encoded certificate from $data to $ssl.

	    my $rv = Net::SSLeay::use_certificate_ASN1($ssl, $data, $len);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $data - certificate data (binary)
	    # $len - length of $data
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   use_certificate_file

	   Loads the first certificate stored in $file into $ssl.

	    my $rv = Net::SSLeay::use_certificate_file($ssl, $file, $type);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $file - (string) file name
	    # $type - (integer)	type - use constants &Net::SSLeay::FILETYPE_PEM	or &Net::SSLeay::FILETYPE_ASN1
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   version

	   Returns SSL/TLS protocol version

	    my $rv = Net::SSLeay::version($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (integer) protocol version
	    #	       0x0002 -	SSL2_VERSION  (SSLv2)
	    #	       0x0300 -	SSL3_VERSION  (SSLv3)
	    #	       0x0301 -	TLS1_VERSION  (TLSv1)
	    #	       0xFEFF -	DTLS1_VERSION (DTLSv1)

       o   want

	   Returns state information for the SSL object	$ssl.

	    my $rv = Net::SSLeay::want($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: state
	    #	       1 - SSL_NOTHING
	    #	       2 - SSL_WRITING
	    #	       3 - SSL_READING
	    #	       4 - SSL_X509_LOOKUP

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_want.html>

       o   write

	   Writes data from the	buffer $data into the specified	$ssl
	   connection.

	    my $rv = Net::SSLeay::write($ssl, $data);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $data - data to be written
	    #
	    # returns: >0 - (success) number of	bytes actually written to the TLS/SSL connection
	    #		0 - write not successful, probably the underlying connection was closed
	    #	       <0 - error

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_write.html>

       o   write_partial

	   NOTE: Does not exactly correspond to	any low	level API function

	   Writes a fragment of	data in	$data from the buffer $data into the
	   specified $ssl connection.

	    my $rv = Net::SSLeay::write_partial($ssl, $from, $count, $data);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $from - (integer)	offset from the	beginning of $data
	    # $count - (integer) length	of data	to be written
	    # $data - data buffer
	    #
	    # returns: >0 - (success) number of	bytes actually written to the TLS/SSL connection
	    #		0 - write not successful, probably the underlying connection was closed
	    #	       <0 - error

       o   set_tlsext_host_name

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-0.9.8f

	   Sets	TLS servername extension on SLL	object $ssl to value $name.

	    my $rv = set_tlsext_host_name($ssl,	$name);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $name - (string) name to be set
	    #
	    # returns: 1 on success, 0 on failure

       Low level API: RAND_* related functions

       Check openssl doc related to RAND stuff
       <http://www.openssl.org/docs/crypto/rand.html>

       o   RAND_add

	   Mixes the $num bytes	at $buf	into the PRNG state.

	    Net::SSLeay::RAND_add($buf,	$num, $entropy);
	    # $buf - buffer with data to be mixed into the PRNG	state
	    # $num - number of bytes in	$buf
	    # $entropy - estimate of how much randomness is contained in $buf (in bytes)
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/RAND_add.html>

       o   RAND_seed

	   Equivalent to "RAND_add" when $num == $entropy.

	    Net::SSLeay::RAND_seed($buf);   # Perlishly	figures	out buf	size
	    # $buf - buffer with data to be mixed into the PRNG	state
	    # $num - number of bytes in	$buf
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/RAND_add.html>

       o   RAND_status

	   Gives PRNG status (seeded enough or not).

	    my $rv = Net::SSLeay::RAND_status();
	    #returns: 1	if the PRNG has	been seeded with enough	data, 0	otherwise

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/RAND_add.html>

       o   RAND_bytes

	   Puts	$num cryptographically strong pseudo-random bytes into $buf.

	    my $rv = Net::SSLeay::RAND_bytes($buf, $num);
	    # $buf - buffer where the random data will be stored
	    # $num - the size (in bytes) of requested random data
	    #
	    # returns: 1 on success, 0 otherwise

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/RAND_bytes.html>

       o   RAND_pseudo_bytes

	   Puts	$num pseudo-random (not	necessarily unpredictable) bytes into
	   $buf.

	    my $rv = Net::SSLeay::RAND_pseudo_bytes($buf, $num);
	    # $buf - buffer where the random data will be stored
	    # $num - the size (in bytes) of requested random data
	    #
	    # returns: 1 if the	bytes generated	are cryptographically strong, 0	otherwise

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/RAND_bytes.html>

       o   RAND_cleanup

	   Erase the PRNG state.

	    Net::SSLeay::RAND_cleanup();
	    # no args, no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/RAND_cleanup.html>

       o   RAND_egd_bytes

	   Queries the entropy gathering daemon	EGD on socket $path for	$bytes
	   bytes.

	    my $rv = Net::SSLeay::RAND_egd_bytes($path,	$bytes);
	    # $path - path to a	socket of entropy gathering daemon EGD
	    # $bytes - number of bytes we want from EGD
	    #
	    # returns: the number of bytes read	from the daemon	on success, and	-1 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/RAND_egd.html>

       o   RAND_file_name

	   Generates a default path for	the random seed	file.

	    my $file = Net::SSLeay::RAND_file_name($num);
	    # $num - maximum size of returned file name
	    #
	    # returns: string with file	name on	success, '' (empty string) on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/RAND_load_file.html>

       o   RAND_load_file

	   Reads $max_bytes of bytes from $file_name and adds them to the
	   PRNG.

	    my $rv = Net::SSLeay::RAND_load_file($file_name, $max_bytes);
	    # $file_name - the name of file
	    # $max_bytes - bytes to read from $file_name; -1 =>	the complete file is read
	    #
	    # returns: the number of bytes read

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/RAND_load_file.html>

       o   RAND_write_file

	   Writes 1024 random bytes to $file_name which	can be used to
	   initialize the PRNG by calling "RAND_load_file" in a	later session.

	    my $rv = Net::SSLeay::RAND_write_file($file_name);
	    # $file_name - the name of file
	    #
	    # returns: the number of bytes written, and	-1 if the bytes	written	were generated without appropriate seed

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/RAND_load_file.html>

       o   RAND_poll

	   Collects some entropy from operating	system and adds	it to the
	   PRNG.

	    my $rv = Net::SSLeay::RAND_poll();
	    # returns: 1 on success, 0 on failure (unable to gather reasonable entropy)

       Low level API: OBJ_* related functions

       o   OBJ_cmp

	   Compares ASN1_OBJECT	$a to ASN1_OBJECT $b.

	    my $rv = Net::SSLeay::OBJ_cmp($a, $b);
	    # $a - value corresponding to openssl's ASN1_OBJECT	structure
	    # $b - value corresponding to openssl's ASN1_OBJECT	structure
	    #
	    # returns: if the two are identical	0 is returned

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/OBJ_nid2obj.html>

       o   OBJ_dup

	   Returns a copy/duplicate of $o.

	    my $rv = Net::SSLeay::OBJ_dup($o);
	    # $o - value corresponding to openssl's ASN1_OBJECT	structure
	    #
	    # returns: value corresponding to openssl's	ASN1_OBJECT structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/OBJ_nid2obj.html>

       o   OBJ_nid2ln

	   Returns long	name for given NID $n.

	    my $rv = Net::SSLeay::OBJ_nid2ln($n);
	    # $n - (integer) NID
	    #
	    # returns: (string)	long name e.g. 'commonName'

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/OBJ_nid2obj.html>

       o   OBJ_ln2nid

	   Returns NID corresponding to	given long name	$n.

	    my $rv = Net::SSLeay::OBJ_ln2nid($s);
	    # $s - (string) long name e.g. 'commonName'
	    #
	    # returns: (integer) NID

       o   OBJ_nid2sn

	   Returns short name for given	NID $n.

	    my $rv = Net::SSLeay::OBJ_nid2sn($n);
	    # $n - (integer) NID
	    #
	    # returns: (string)	short name e.g.	'CN'

	   Example:

	    print Net::SSLeay::OBJ_nid2sn(&Net::SSLeay::NID_commonName);

       o   OBJ_sn2nid

	   Returns NID corresponding to	given short name $s.

	    my $rv = Net::SSLeay::OBJ_sn2nid($s);
	    # $s - (string) short name e.g. 'CN'
	    #
	    # returns: (integer) NID

	   Example:

	    print "NID_commonName constant=", &Net::SSLeay::NID_commonName;
	    print "OBJ_sn2nid('CN')=", Net::SSLeay::OBJ_sn2nid('CN');

       o   OBJ_nid2obj

	   Returns ASN1_OBJECT for given NID $n.

	    my $rv = Net::SSLeay::OBJ_nid2obj($n);
	    # $n - (integer) NID
	    #
	    # returns: value corresponding to openssl's	ASN1_OBJECT structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/OBJ_nid2obj.html>

       o   OBJ_obj2nid

	   Returns NID corresponding to	given ASN1_OBJECT $o.

	    my $rv = Net::SSLeay::OBJ_obj2nid($o);
	    # $o - value corresponding to openssl's ASN1_OBJECT	structure
	    #
	    # returns: (integer) NID

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/OBJ_nid2obj.html>

       o   OBJ_txt2obj

	   Converts the	text string s into an ASN1_OBJECT structure. If
	   $no_name is 0 then long names (e.g. 'commonName') and short names
	   (e.g. 'CN') will be interpreted as well as numerical	forms (e.g.
	   '2.5.4.3'). If $no_name is 1	only the numerical form	is acceptable.

	    my $rv = Net::SSLeay::OBJ_txt2obj($s, $no_name);
	    # $s - text	string to be converted
	    # $no_name - (integer) 0 or	1
	    #
	    # returns: value corresponding to openssl's	ASN1_OBJECT structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/OBJ_nid2obj.html>

       o   OBJ_obj2txt

	   Converts the	ASN1_OBJECT a into a textual representation.

	    Net::SSLeay::OBJ_obj2txt($a, $no_name);
	    # $a - value corresponding to openssl's ASN1_OBJECT	structure
	    # $no_name - (integer) 0 or	1
	    #
	    # returns: textual representation e.g. 'commonName'	($no_name=0), '2.5.4.3'	($no_name=1)

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/OBJ_nid2obj.html>

       o   OBJ_txt2nid

	   Returns NID corresponding to	text string $s which can be a long
	   name, a short name or the numerical representation of an object.

	    my $rv = Net::SSLeay::OBJ_txt2nid($s);
	    # $s - (string) e.g. 'commonName' or 'CN' or '2.5.4.3'
	    #
	    # returns: (integer) NID

	   Example:

	    my $nid = Net::SSLeay::OBJ_txt2nid('2.5.4.3');
	    Net::SSLeay::OBJ_nid2sn($n);

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/OBJ_nid2obj.html>

       Low level API: ASN1_INTEGER_* related functions

       o   ASN1_INTEGER_new

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Creates a new ASN1_INTEGER structure.

	    my $rv = Net::SSLeay::ASN1_INTEGER_new();
	    #
	    # returns: value corresponding to openssl's	ASN1_INTEGER structure (0 on failure)

       o   ASN1_INTEGER_free

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Free	an allocated ASN1_INTEGER structure.

	    Net::SSLeay::ASN1_INTEGER_free($i);
	    # $i - value corresponding to openssl's ASN1_INTEGER structure
	    #
	    # returns: no return value

       o   ASN1_INTEGER_get

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns integer value of given ASN1_INTEGER object.

	   BEWARE: If the value	stored in ASN1_INTEGER is greater than max.
	   integer that	can be stored in 'long'	type (usually 32bit but	may
	   vary	according to platform) then this function will return -1.  For
	   getting large ASN1_INTEGER values consider using
	   "P_ASN1_INTEGER_get_dec" or "P_ASN1_INTEGER_get_hex".

	    my $rv = Net::SSLeay::ASN1_INTEGER_get($a);
	    # $a - value corresponding to openssl's ASN1_INTEGER structure
	    #
	    # returns: integer value of	ASN1_INTEGER object in $a

       o   ASN1_INTEGER_set

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Sets	value of given ASN1_INTEGER object to value $val

	   BEWARE: $val	has max. limit (= max. integer that can	be stored in
	   'long' type).  For setting large ASN1_INTEGER values	consider using
	   "P_ASN1_INTEGER_set_dec" or "P_ASN1_INTEGER_set_hex".

	    my $rv = Net::SSLeay::ASN1_INTEGER_set($i, $val);
	    # $i - value corresponding to openssl's ASN1_INTEGER structure
	    # $val - integer value
	    #
	    # returns: 1 on success, 0 on failure

       o   P_ASN1_INTEGER_get_dec

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns string with decimal representation of integer value of
	   given ASN1_INTEGER object.

	    Net::SSLeay::P_ASN1_INTEGER_get_dec($i);
	    # $i - value corresponding to openssl's ASN1_INTEGER structure
	    #
	    # returns: string with decimal representation

       o   P_ASN1_INTEGER_get_hex

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns string with hexadecimal representation of integer value of
	   given ASN1_INTEGER object.

	    Net::SSLeay::P_ASN1_INTEGER_get_hex($i);
	    # $i - value corresponding to openssl's ASN1_INTEGER structure
	    #
	    # returns: string with hexadecimal representation

       o   P_ASN1_INTEGER_set_dec

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Sets	value of given ASN1_INTEGER object to value $val (decimal
	   string, suitable for	large integers)

	    Net::SSLeay::P_ASN1_INTEGER_set_dec($i, $str);
	    # $i - value corresponding to openssl's ASN1_INTEGER structure
	    # $str - string with decimal representation
	    #
	    # returns: 1 on success, 0 on failure

       o   P_ASN1_INTEGER_set_hex

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Sets	value of given ASN1_INTEGER object to value $val (hexadecimal
	   string, suitable for	large integers)

	    Net::SSLeay::P_ASN1_INTEGER_set_hex($i, $str);
	    # $i - value corresponding to openssl's ASN1_INTEGER structure
	    # $str - string with hexadecimal representation
	    #
	    # returns: 1 on success, 0 on failure

       Low level API: ASN1_STRING_* related functions

       o   P_ASN1_STRING_get

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns string value	of given ASN1_STRING object.

	    Net::SSLeay::P_ASN1_STRING_get($s, $utf8_decode);
	    # $s - value corresponding to openssl's ASN1_STRING	structure
	    # $utf8_decode - [optional]	0 or 1 whether the returned value should be utf8 decoded (default=0)
	    #
	    # returns: string

	    $string = Net::SSLeay::P_ASN1_STRING_get($s);
	    #is	the same as:
	    $string = Net::SSLeay::P_ASN1_STRING_get($s, 0);

       Low level API: ASN1_TIME_* related functions

       o   ASN1_TIME_new

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before

	    my $time = ASN1_TIME_new();
	    # returns: value corresponding to openssl's	ASN1_TIME structure

       o   ASN1_TIME_free

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before

	    ASN1_TIME_free($time);
	    # $time - value corresponding to openssl's ASN1_TIME structure

       o   ASN1_TIME_set

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before

	    ASN1_TIME_set($time, $t);
	    # $time - value corresponding to openssl's ASN1_TIME structure
	    # $t - time	value in seconds since 1.1.1970

	   BEWARE: It is platform dependent how	this function will handle
	   dates after 2038.  Although perl's integer is large enough the
	   internal implementation of this function is dependent on the	size
	   of time_t structure (32bit time_t has problem with 2038).

	   If you want to safely set date and time after 2038 use function
	   "P_ASN1_TIME_set_isotime".

       o   P_ASN1_TIME_get_isotime

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before;
	   requires at least openssl-0.9.7e

	   NOTE: Does not exactly correspond to	any low	level API function

	   Gives ISO-8601 string representation	of ASN1_TIME structure.

	    my $datetime_string	= P_ASN1_TIME_get_isotime($time);
	    # $time - value corresponding to openssl's ASN1_TIME structure
	    #
	    # returns: datetime	string like '2033-05-16T20:39:37Z' or '' on failure

	   The output format is	compatible with	module
	   DateTime::Format::RFC3339

       o   P_ASN1_TIME_set_isotime

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before;
	   requires at least openssl-0.9.7e

	   NOTE: Does not exactly correspond to	any low	level API function

	   Sets	time and date value of ANS1_time structure.

	    my $rv = P_ASN1_TIME_set_isotime($time, $string);
	    # $time - value corresponding to openssl's ASN1_TIME structure
	    # $string -	ISO-8601 timedate string like '2033-05-16T20:39:37Z'
	    #
	    # returns: 1 on success, 0 on failure

	   The $string parameter has to	be in full form	like
	   "2012-03-22T23:55:33" or "2012-03-22T23:55:33Z" or
	   "2012-03-22T23:55:33CET". Short forms like "2012-03-22T23:55" or
	   "2012-03-22"	are not	supported.

       o   P_ASN1_TIME_put2string

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before, has
	   bugs	with openssl-0.9.8i

	   NOTE: Does not exactly correspond to	any low	level API function

	   Gives string	representation of ASN1_TIME structure.

	    my $str = P_ASN1_TIME_put2string($time);
	    # $time - value corresponding to openssl's ASN1_TIME structure
	    #
	    # returns: datetime	string like 'May 16 20:39:37 2033 GMT'

       o   P_ASN1_UTCTIME_put2string

	   NOTE: deprecated function, only for backward	compatibility, just an
	   alias for "P_ASN1_TIME_put2string"

       Low level API: X509_* related functions

       o   X509_new

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Allocates and initializes a X509 structure.

	    my $rv = Net::SSLeay::X509_new();
	    #
	    # returns: value corresponding to openssl's	X509 structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_new.html>

       o   X509_free

	   Frees up the	X509 structure.

	    Net::SSLeay::X509_free($a);
	    # $a - value corresponding to openssl's X509 structure
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_new.html>

       o   X509_check_host

	   COMPATIBILITY: not available	in Net-SSLeay-1.68 and before;
	   requires at least OpenSSL 1.0.2.

	   Checks f the	certificate Subject Alternative	Name (SAN) or Subject
	   CommonName (CN) matches the specified host name.

	    my $rv = Net::SSLeay::X509_check_host($cert, $name,	$flags,	$peername);
	    # $cert - value corresponding to openssl's X509 structure
	    # $name - host name	to check
	    # $flags (optional,	default: 0) - can be the bitwise OR of:
	    #	&Net::SSLeay::X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT
	    #	&Net::SSLeay::X509_CHECK_FLAG_NO_WILDCARDS
	    #	&Net::SSLeay::X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS
	    #	&Net::SSLeay::X509_CHECK_FLAG_MULTI_LABEL_WILDCARDS
	    #	&Net::SSLeay::X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS
	    # $peername	(optional) - If	not omitted and	$host matches $cert,
	    #			     a copy of the matching SAN	or CN from
	    #			     the peer certificate is stored in $peername.
	    #
	    # returns:
	    #	1 for a	successful match
	    #	0 for a	failed match
	    #  -1 for an internal error
	    #  -2 if the input is malformed

	   Check openssl doc
	   <https://www.openssl.org/docs/crypto/X509_check_host.html>.

       o   X509_check_email

	   COMPATIBILITY: not available	in Net-SSLeay-1.68 and before;
	   requires at least OpenSSL 1.0.2.

	   Checks if the certificate matches the specified email address.

	    my $rv = Net::SSLeay::X509_check_email($cert, $address, $flags);
	    # $cert - value corresponding to openssl's X509 structure
	    # $address - email address to check
	    # $flags (optional,	default: 0) - see X509_check_host()
	    #
	    # returns: see X509_check_host()

	   Check openssl doc
	   <https://www.openssl.org/docs/crypto/X509_check_email.html>.

       o   X509_check_ip

	   COMPATIBILITY: not available	in Net-SSLeay-1.68 and before;
	   requires at least OpenSSL 1.0.2.

	   Checks if the certificate matches the specified IPv4	or IPv6
	   address.

	    my $rv = Net::SSLeay::X509_check_email($cert, $address, $flags);
	    # $cert - value corresponding to openssl's X509 structure
	    # $address - IP address to check in	binary format, in network byte order
	    # $flags (optional,	default: 0) - see X509_check_host()
	    #
	    # returns: see X509_check_host()

	   Check openssl doc
	   <https://www.openssl.org/docs/crypto/X509_check_ip.html>.

       o   X509_check_ip_asc

	   COMPATIBILITY: not available	in Net-SSLeay-1.68 and before;
	   requires at least OpenSSL 1.0.2.

	   Checks if the certificate matches the specified IPv4	or IPv6
	   address.

	    my $rv = Net::SSLeay::X509_check_email($cert, $address, $flags);
	    # $cert - value corresponding to openssl's X509 structure
	    # $address - IP address to check in	text representation
	    # $flags (optional,	default: 0) - see X509_check_host()
	    #
	    # returns: see X509_check_host()

	   Check openssl doc
	   <https://www.openssl.org/docs/crypto/X509_check_ip_asc.html>.

       o   X509_certificate_type

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns bitmask with	type of	certificate $x.

	    my $rv = Net::SSLeay::X509_certificate_type($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: (integer) bitmask with certificate type

	    #to	decode bitmask returned	by this	function use these constants:
	    &Net::SSLeay::EVP_PKS_DSA
	    &Net::SSLeay::EVP_PKS_EC
	    &Net::SSLeay::EVP_PKS_RSA
	    &Net::SSLeay::EVP_PKT_ENC
	    &Net::SSLeay::EVP_PKT_EXCH
	    &Net::SSLeay::EVP_PKT_EXP
	    &Net::SSLeay::EVP_PKT_SIGN
	    &Net::SSLeay::EVP_PK_DH
	    &Net::SSLeay::EVP_PK_DSA
	    &Net::SSLeay::EVP_PK_EC
	    &Net::SSLeay::EVP_PK_RSA

       o   X509_digest

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Computes digest/fingerprint of X509 $data using $type hash
	   function.

	    my $digest_value = Net::SSLeay::X509_digest($data, $type);
	    # $data - value corresponding to openssl's X509 structure
	    # $type - value corresponding to openssl's EVP_MD structure	- e.g. got via EVP_get_digestbyname()
	    #
	    # returns: hash value (binary)

	    #to	get printable (hex) value of digest use:
	    print unpack('H*', $digest_value);

       o   X509_issuer_and_serial_hash

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Sort	of a checksum of issuer	name and serial	number of X509
	   certificate $x.  The	result is not a	full hash (e.g.	sha-1),	it is
	   kind-of-a-hash truncated to the size	of 'unsigned long' (32 bits).
	   The resulting value might differ across different openssl versions
	   for the same	X509 certificate.

	    my $rv = Net::SSLeay::X509_issuer_and_serial_hash($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: number representing checksum

       o   X509_issuer_name_hash

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Sort	of a checksum of issuer	name of	X509 certificate $x.  The
	   result is not a full	hash (e.g. sha-1), it is kind-of-a-hash
	   truncated to	the size of 'unsigned long' (32	bits).	The resulting
	   value might differ across different openssl versions	for the	same
	   X509	certificate.

	    my $rv = Net::SSLeay::X509_issuer_name_hash($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: number representing checksum

       o   X509_subject_name_hash

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Sort	of a checksum of subject name of X509 certificate $x.  The
	   result is not a full	hash (e.g. sha-1), it is kind-of-a-hash
	   truncated to	the size of 'unsigned long' (32	bits).	The resulting
	   value might differ across different openssl versions	for the	same
	   X509	certificate.

	    my $rv = Net::SSLeay::X509_subject_name_hash($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: number representing checksum

       o   X509_pubkey_digest

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-0.9.7

	   Computes digest/fingerprint of public key from X509 certificate
	   $data using $type hash function.

	    my $digest_value = Net::SSLeay::X509_pubkey_digest($data, $type);
	    # $data - value corresponding to openssl's X509 structure
	    # $type - value corresponding to openssl's EVP_MD structure	- e.g. got via EVP_get_digestbyname()
	    #
	    # returns: hash value (binary)

	    #to	get printable (hex) value of digest use:
	    print unpack('H*', $digest_value);

       o   X509_set_issuer_name

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Sets	issuer of X509 certificate $x to $name.

	    my $rv = Net::SSLeay::X509_set_issuer_name($x, $name);
	    # $x - value corresponding to openssl's X509 structure
	    # $name - value corresponding to openssl's X509_NAME structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_set_pubkey

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Sets	public key of X509 certificate $x to $pkey.

	    my $rv = Net::SSLeay::X509_set_pubkey($x, $pkey);
	    # $x - value corresponding to openssl's X509 structure
	    # $pkey - value corresponding to openssl's EVP_PKEY	structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_set_serialNumber

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Sets	serial number of X509 certificate $x to	$serial.

	    my $rv = Net::SSLeay::X509_set_serialNumber($x, $serial);
	    # $x - value corresponding to openssl's X509 structure
	    # $serial -	value corresponding to openssl's ASN1_INTEGER structure
	    #
	    # returns: 1 on success, 0 on failure

	    #to	create $serial value use one of	these:
	    $serial = Net::SSLeay::P_ASN1_INTEGER_set_hex('45ad6f');
	    $serial = Net::SSLeay::P_ASN1_INTEGER_set_dec('7896541238529631478');
	    $serial = Net::SSLeay::ASN1_INTEGER_set(45896);

       o   X509_set_subject_name

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Sets	subject	of X509	certificate $x to $name.

	    my $rv = Net::SSLeay::X509_set_subject_name($x, $name);
	    # $x - value corresponding to openssl's X509 structure
	    # $name - value corresponding to openssl's X509_NAME structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_set_version

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Set 'version' value for X509	certificate $ to $version.

	    my $rv = Net::SSLeay::X509_set_version($x, $version);
	    # $x - value corresponding to openssl's X509 structure
	    # $version - (integer) version number
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_sign

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Sign	X509 certificate $x with private key $pkey (using digest
	   algorithm $md).

	    my $rv = Net::SSLeay::X509_sign($x,	$pkey, $md);
	    # $x - value corresponding to openssl's X509 structure
	    # $pkey - value corresponding to openssl's EVP_PKEY	structure
	    # $md - value corresponding	to openssl's EVP_MD structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_verify

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Verifies X509 object	$a using public	key $r (pubkey of issuing CA).

	    my $rv = Net::SSLeay::X509_verify($x, $r);
	    # $x - value corresponding to openssl's X509 structure
	    # $r - value corresponding to openssl's EVP_PKEY structure
	    #
	    # returns: 0 - verify failure, 1 - verify OK, <0 - error

       o   X509_get_ext_count

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns the total number of extensions in X509 object $x.

	    my $rv = Net::SSLeay::X509_get_ext_count($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: count of	extensions

       o   X509_get_pubkey

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns public key corresponding to given X509 object $x.

	    my $rv = Net::SSLeay::X509_get_pubkey($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: value corresponding to openssl's	EVP_PKEY structure (0 on failure)

	   NOTE: This method returns only the public key's key bits, without
	   the algorithm or parameters.	 Use "X509_get_X509_PUBKEY()" to
	   return the full public key (SPKI) instead.

       o   X509_get_X509_PUBKEY

	   COMPATIBILITY: not available	in Net-SSLeay-1.72 and before

	   Returns the full public key (SPKI) of given X509 certificate	$x.

	    Net::SSLeay::X509_get_X509_PUBKEY($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: public key data in DER format (binary)

       o   X509_get_serialNumber

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns serial number of X509 certificate $x.

	    my $rv = Net::SSLeay::X509_get_serialNumber($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: value corresponding to openssl's	ASN1_INTEGER structure (0 on failure)

	   See "P_ASN1_INTEGER_get_dec", "P_ASN1_INTEGER_get_hex" or
	   "ASN1_INTEGER_get" to decode	ASN1_INTEGER object.

       o   X509_get_version

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns 'version' value of given X509 certificate $x.

	    my $rv = Net::SSLeay::X509_get_version($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: (integer) version

       o   X509_get_ext

	   Returns X509_EXTENSION from $x509 based on given position/index.

	    my $rv = Net::SSLeay::X509_get_ext($x509, $index);
	    # $x509 - value corresponding to openssl's X509 structure
	    # $index - (integer) position/index	of extension within $x509
	    #
	    # returns: value corresponding to openssl's	X509_EXTENSION structure (0 on failure)

       o   X509_get_ext_by_NID

	   Returns X509_EXTENSION from $x509 based on given NID.

	    my $rv = Net::SSLeay::X509_get_ext_by_NID($x509, $nid, $loc);
	    # $x509 - value corresponding to openssl's X509 structure
	    # $nid - (integer) NID value
	    # $loc - (integer) position	to start lookup	at
	    #
	    # returns: position/index of extension, negative value on error
	    #	       call Net::SSLeay::X509_get_ext($x509, $rv) to get the actual extension

       o   X509_get_fingerprint

	   Returns fingerprint of certificate $cert.

	   NOTE: Does not exactly correspond to	any low	level API function.
	   The implementation is basen on openssl's "X509_digest()".

	    Net::SSLeay::X509_get_fingerprint($x509, $type);
	    # $x509 - value corresponding to openssl's X509 structure
	    # $type - (string) digest type, currently supported	values:
	    #	      "md5"
	    #	      "sha1"
	    #	      "sha256"
	    #	      "ripemd160"
	    #
	    # returns: certificate digest - hexadecimal	string (NOT binary data!)

       o   X509_get_issuer_name

	   Return an X509_NAME object representing the issuer of the
	   certificate $cert.

	    my $rv = Net::SSLeay::X509_get_issuer_name($cert);
	    # $cert - value corresponding to openssl's X509 structure
	    #
	    # returns: value corresponding to openssl's	X509_NAME structure (0 on failure)

       o   X509_get_notAfter

	   Return an object giving the time after which	the certificate	$cert
	   is not valid.

	    my $rv = Net::SSLeay::X509_get_notAfter($cert);
	    # $cert - value corresponding to openssl's X509 structure
	    #
	    # returns: value corresponding to openssl's	ASN1_TIME structure (0 on failure)

	   To get human	readable/printable form	the return value you can use:

	    my $time = Net::SSLeay::X509_get_notAfter($cert);
	    print "notAfter=", Net::SSLeay::P_ASN1_TIME_get_isotime($time), "\n";

       o   X509_get_notBefore

	   Return an object giving the time before which the certificate $cert
	   is not valid

	    my $rv = Net::SSLeay::X509_get_notBefore($cert);
	    # $cert - value corresponding to openssl's X509 structure
	    #
	    # returns: value corresponding to openssl's	ASN1_TIME structure (0 on failure)

	   To get human	readable/printable form	the return value you can use:

	    my $time = Net::SSLeay::X509_get_notBefore($cert);
	    print "notBefore=",	Net::SSLeay::P_ASN1_TIME_get_isotime($time), "\n";

       o   X509_get_subjectAltNames

	   NOTE: Does not exactly correspond to	any low	level API function.

	   Returns the list of alternative subject names from X509 certificate
	   $cert.

	    my @rv = Net::SSLeay::X509_get_subjectAltNames($cert);
	    # $cert - value corresponding to openssl's X509 structure
	    #
	    # returns: list containing pairs - name_type (integer), name_value (string)
	    #	       where name_type can be:
	    #	       0 - GEN_OTHERNAME
	    #	       1 - GEN_EMAIL
	    #	       2 - GEN_DNS
	    #	       3 - GEN_X400
	    #	       4 - GEN_DIRNAME
	    #	       5 - GEN_EDIPARTY
	    #	       6 - GEN_URI
	    #	       7 - GEN_IPADD
	    #	       8 - GEN_RID

	   Note: type 7	- GEN_IPADD contains the IP address as a packed	binary
	   address.

       o   X509_get_subject_name

	   Returns the subject of the certificate $cert.

	    my $rv = Net::SSLeay::X509_get_subject_name($cert);
	    # $cert - value corresponding to openssl's X509 structure
	    #
	    # returns: value corresponding to openssl's	X509_NAME structure (0 on failure)

       o   X509_gmtime_adj

	   Adjust th ASN1_TIME object to the timestamp (in GMT).

	    my $rv = Net::SSLeay::X509_gmtime_adj($s, $adj);
	    # $s - value corresponding to openssl's ASN1_TIME structure
	    # $adj - timestamp (seconds	since 1.1.1970)
	    #
	    # returns: value corresponding to openssl's	ASN1_TIME structure (0 on failure)

	   BEWARE: this	function may fail for dates after 2038 as it is
	   dependent on	time_t size on your system (32bit time_t does not work
	   after 2038).	Consider using "P_ASN1_TIME_set_isotime" instead).

       o   X509_load_cert_crl_file

	   Takes PEM file and loads all	X509 certificates and X509 CRLs	from
	   that	file into X509_LOOKUP structure.

	    my $rv = Net::SSLeay::X509_load_cert_crl_file($ctx,	$file, $type);
	    # $ctx - value corresponding to openssl's X509_LOOKUP structure
	    # $file - (string) file name
	    # $type - (integer)	type - use constants &Net::SSLeay::FILETYPE_PEM	or &Net::SSLeay::FILETYPE_ASN1
	    #			       if not FILETYPE_PEM then	behaves	as Net::SSLeay::X509_load_cert_file()
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_load_cert_file

	   Loads/adds X509 certificate from $file to X509_LOOKUP structure

	    my $rv = Net::SSLeay::X509_load_cert_file($ctx, $file, $type);
	    # $ctx - value corresponding to openssl's X509_LOOKUP structure
	    # $file - (string) file name
	    # $type - (integer)	type - use constants &Net::SSLeay::FILETYPE_PEM	or &Net::SSLeay::FILETYPE_ASN1
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_load_crl_file

	   Loads/adds X509 CRL from $file to X509_LOOKUP structure

	    my $rv = Net::SSLeay::X509_load_crl_file($ctx, $file, $type);
	    # $ctx - value corresponding to openssl's X509_LOOKUP structure
	    # $file - (string) file name
	    # $type - (integer)	type - use constants &Net::SSLeay::FILETYPE_PEM	or &Net::SSLeay::FILETYPE_ASN1
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_policy_level_get0_node

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_level_get0_node($level, $i);
	    # $level - value corresponding to openssl's	X509_POLICY_LEVEL structure
	    # $i - (integer) index/position
	    #
	    # returns: value corresponding to openssl's	X509_POLICY_NODE structure (0 on failure)

       o   X509_policy_level_node_count

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_level_node_count($level);
	    # $level - value corresponding to openssl's	X509_POLICY_LEVEL structure
	    #
	    # returns: (integer) node count

       o   X509_policy_node_get0_parent

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_node_get0_parent($node);
	    # $node - value corresponding to openssl's X509_POLICY_NODE	structure
	    #
	    # returns: value corresponding to openssl's	X509_POLICY_NODE structure (0 on failure)

       o   X509_policy_node_get0_policy

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_node_get0_policy($node);
	    # $node - value corresponding to openssl's X509_POLICY_NODE	structure
	    #
	    # returns: value corresponding to openssl's	ASN1_OBJECT structure (0 on failure)

       o   X509_policy_node_get0_qualifiers

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_node_get0_qualifiers($node);
	    # $node - value corresponding to openssl's X509_POLICY_NODE	structure
	    #
	    # returns: value corresponding to openssl's	STACK_OF(POLICYQUALINFO) structure (0 on failure)

       o   X509_policy_tree_free

	   ??? (more info needed)

	    Net::SSLeay::X509_policy_tree_free($tree);
	    # $tree - value corresponding to openssl's X509_POLICY_TREE	structure
	    #
	    # returns: no return value

       o   X509_policy_tree_get0_level

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_tree_get0_level($tree, $i);
	    # $tree - value corresponding to openssl's X509_POLICY_TREE	structure
	    # $i - (integer) level index
	    #
	    # returns: value corresponding to openssl's	X509_POLICY_LEVEL structure (0 on failure)

       o   X509_policy_tree_get0_policies

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_tree_get0_policies($tree);
	    # $tree - value corresponding to openssl's X509_POLICY_TREE	structure
	    #
	    # returns: value corresponding to openssl's	X509_POLICY_NODE structure (0 on failure)

       o   X509_policy_tree_get0_user_policies

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_tree_get0_user_policies($tree);
	    # $tree - value corresponding to openssl's X509_POLICY_TREE	structure
	    #
	    # returns: value corresponding to openssl's	X509_POLICY_NODE structure (0 on failure)

       o   X509_policy_tree_level_count

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_tree_level_count($tree);
	    # $tree - value corresponding to openssl's X509_POLICY_TREE	structure
	    #
	    # returns: (integer) count

       o   X509_verify_cert_error_string

	   Returns a human readable error string for verification error	$n.

	    my $rv = Net::SSLeay::X509_verify_cert_error_string($n);
	    # $n - (long) numeric error	code
	    #
	    # returns: error string

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_STORE_CTX_get_error.html>

       o   P_X509_add_extensions

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Adds	one or more X509 extensions to X509 object $x.

	    my $rv = Net::SSLeay::P_X509_add_extensions($x, $ca_cert, $nid, $value);
	    # $x - value corresponding to openssl's X509 structure
	    # $ca_cert - value corresponding to	openssl's X509 structure (issuer's cert	- necessary for	sertting NID_authority_key_identifier)
	    # $nid - NID identifying extension to be set
	    # $value - extension value
	    #
	    # returns: 1 on success, 0 on failure

	   You can set more extensions at once:

	    my $rv = Net::SSLeay::P_X509_add_extensions($x509, $ca_cert,
			   &Net::SSLeay::NID_key_usage => 'digitalSignature,keyEncipherment',
			   &Net::SSLeay::NID_subject_key_identifier => 'hash',
			   &Net::SSLeay::NID_authority_key_identifier => 'keyid',
			   &Net::SSLeay::NID_authority_key_identifier => 'issuer',
			   &Net::SSLeay::NID_basic_constraints => 'CA:FALSE',
			   &Net::SSLeay::NID_ext_key_usage => 'serverAuth,clientAuth',
			   &Net::SSLeay::NID_netscape_cert_type	=> 'server',
			   &Net::SSLeay::NID_subject_alt_name => 'DNS:s1.dom.com,DNS:s2.dom.com,DNS:s3.dom.com',
		     );

       o   P_X509_copy_extensions

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Copies X509 extensions from X509_REQ	object to X509 object -	handy
	   when	you need to turn X509_REQ into X509 certificate.

	    Net::SSLeay::P_X509_copy_extensions($x509_req, $x509, $override);
	    # $x509_req	- value	corresponding to openssl's X509_REQ structure
	    # $x509 - value corresponding to openssl's X509 structure
	    # $override	- (integer) flag indication whether to override	already	existing items in $x509	(default 1)
	    #
	    # returns: 1 on success, 0 on failure

       o   P_X509_get_crl_distribution_points

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-0.9.7

	   Get the list	of CRL distribution points from	X509 certificate.

	    my @cdp = Net::SSLeay::P_X509_get_crl_distribution_points($x509);
	    # $x509 - value corresponding to openssl's X509 structure
	    #
	    # returns: list of distribution points (usually URLs)

       o   P_X509_get_ext_key_usage

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-0.9.7

	   Gets	the list of extended key usage of given	X509 certificate
	   $cert.

	    my @ext_usage = Net::SSLeay::P_X509_get_ext_key_usage($cert, $format);
	    # $cert - value corresponding to openssl's X509 structure
	    # $format -	choose type of return values: 0=OIDs, 1=NIDs, 2=shortnames, 3=longnames
	    #
	    # returns: list of values

	   Examples:

	    my @extkeyusage_oid	= Net::SSLeay::P_X509_get_ext_key_usage($x509,0);
	    # returns for example: ("1.3.6.1.5.5.7.3.1", "1.3.6.1.5.5.7.3.2")

	    my @extkeyusage_nid	= Net::SSLeay::P_X509_get_ext_key_usage($x509,1);
	    # returns for example: (129, 130)

	    my @extkeyusage_sn	= Net::SSLeay::P_X509_get_ext_key_usage($x509,2);
	    # returns for example: ("serverAuth", "clientAuth")

	    my @extkeyusage_ln	= Net::SSLeay::P_X509_get_ext_key_usage($x509,3);
	    # returns for example: ("TLS Web Server Authentication",  "TLS Web Client Authentication")

       o   P_X509_get_key_usage

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Gets	the list of key	usage of given X509 certificate	$cert.

	    my @keyusage = Net::SSLeay::P_X509_get_key_usage($cert);
	    # $cert - value corresponding to openssl's X509 structure
	    #
	    # returns: list of key usage values	which can be none, one or more from the	following list:
	    #	       "digitalSignature"
	    #	       "nonRepudiation"
	    #	       "keyEncipherment"
	    #	       "dataEncipherment"
	    #	       "keyAgreement"
	    #	       "keyCertSign"
	    #	       "cRLSign"
	    #	       "encipherOnly"
	    #	       "decipherOnly"

       o   P_X509_get_netscape_cert_type

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Gets	the list of Netscape cert types	of given X509 certificate
	   $cert.

	    Net::SSLeay::P_X509_get_netscape_cert_type($cert);
	    # $cert - value corresponding to openssl's X509 structure
	    #
	    # returns: list of Netscape	type values which can be none, one or more from	the following list:
	    #	       "client"
	    #	       "server"
	    #	       "email"
	    #	       "objsign"
	    #	       "reserved"
	    #	       "sslCA"
	    #	       "emailCA"
	    #	       "objCA"

       o   P_X509_get_pubkey_alg

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns ASN1_OBJECT corresponding to	X509 certificate public	key
	   algorithm.

	    my $rv = Net::SSLeay::P_X509_get_pubkey_alg($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: value corresponding to openssl's	ASN1_OBJECT structure (0 on failure)

	   To get textual representation use:

	    my $alg = Net::SSLeay::OBJ_obj2txt(Net::SSLeay::P_X509_get_pubkey_alg($x509));
	    # returns for example: "rsaEncryption"

       o   P_X509_get_signature_alg

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns ASN1_OBJECT corresponding to	X509 signarite key algorithm.

	    my $rv = Net::SSLeay::P_X509_get_signature_alg($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: value corresponding to openssl's	ASN1_OBJECT structure (0 on failure)

	   To get textual representation use:

	    my $alg = Net::SSLeay::OBJ_obj2txt(Net::SSLeay::P_X509_get_signature_alg($x509))
	    # returns for example: "sha1WithRSAEncryption"

       Low level API: X509_REQ_* related functions

       o   X509_REQ_new

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Creates a new X509_REQ structure.

	    my $rv = Net::SSLeay::X509_REQ_new();
	    #
	    # returns: value corresponding to openssl's	X509_REQ structure (0 on failure)

       o   X509_REQ_free

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Free	an allocated X509_REQ structure.

	    Net::SSLeay::X509_REQ_free($x);
	    # $x - value corresponding to openssl's X509_REQ structure
	    #
	    # returns: no return value

       o   X509_REQ_add1_attr_by_NID

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Adds	an attribute whose name	is defined by a	NID $nid. The field
	   value to be added is	in $bytes.

	    my $rv = Net::SSLeay::X509_REQ_add1_attr_by_NID($req, $nid,	$type, $bytes);
	    # $req - value corresponding to openssl's X509_REQ structure
	    # $nid - (integer) NID value
	    # $type - (integer)	type of	data in	$bytes (see below)
	    # $bytes - data to be set
	    #
	    # returns: 1 on success, 0 on failure

	    # values for $type - use constants:
	    &Net::SSLeay::MBSTRING_UTF8	    - $bytes contains utf8 encoded data
	    &Net::SSLeay::MBSTRING_ASC	    - $bytes contains ASCII data

       o   X509_REQ_digest

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Computes digest/fingerprint of X509_REQ $data using $type hash
	   function.

	    my $digest_value = Net::SSLeay::X509_REQ_digest($data, $type);
	    # $data - value corresponding to openssl's X509_REQ	structure
	    # $type - value corresponding to openssl's EVP_MD structure	- e.g. got via EVP_get_digestbyname()
	    #
	    # returns: hash value (binary)

	    #to	get printable (hex) value of digest use:
	    print unpack('H*', $digest_value);

       o   X509_REQ_get_attr_by_NID

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Retrieve the	next index matching $nid after $lastpos	($lastpos
	   should initially be set to -1).

	    my $rv = Net::SSLeay::X509_REQ_get_attr_by_NID($req, $nid, $lastpos=-1);
	    # $req - value corresponding to openssl's X509_REQ structure
	    # $nid - (integer) NID value
	    # $lastpos - [optional] (integer) index where to start search (default -1)
	    #
	    # returns: index (-1 if there are no more entries)

	   Note: use "P_X509_REQ_get_attr" to get the actual attribute value -
	   e.g.

	    my $index =	Net::SSLeay::X509_REQ_get_attr_by_NID($req, $nid);
	    my @attr_values = Net::SSLeay::P_X509_REQ_get_attr($req, $index);

       o   X509_REQ_get_attr_by_OBJ

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Retrieve the	next index matching $obj after $lastpos	($lastpos
	   should initially be set to -1).

	    my $rv = Net::SSLeay::X509_REQ_get_attr_by_OBJ($req, $obj, $lastpos=-1);
	    # $req - value corresponding to openssl's X509_REQ structure
	    # $obj - value corresponding to openssl's ASN1_OBJECT structure
	    # $lastpos - [optional] (integer) index where to start search (default -1)
	    #
	    # returns: index (-1 if there are no more entries)

	   Note: use "P_X509_REQ_get_attr" to get the actual attribute value -
	   e.g.

	    my $index =	Net::SSLeay::X509_REQ_get_attr_by_NID($req, $nid);
	    my @attr_values = Net::SSLeay::P_X509_REQ_get_attr($req, $index);

       o   X509_REQ_get_attr_count

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns the total number of attributes in $req.

	    my $rv = Net::SSLeay::X509_REQ_get_attr_count($req);
	    # $req - value corresponding to openssl's X509_REQ structure
	    #
	    # returns: (integer) items count

       o   X509_REQ_get_pubkey

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns public key corresponding to given X509_REQ object $x.

	    my $rv = Net::SSLeay::X509_REQ_get_pubkey($x);
	    # $x - value corresponding to openssl's X509_REQ structure
	    #
	    # returns: value corresponding to openssl's	EVP_PKEY structure (0 on failure)

       o   X509_REQ_get_subject_name

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns X509_NAME object corresponding to subject name of given
	   X509_REQ object $x.

	    my $rv = Net::SSLeay::X509_REQ_get_subject_name($x);
	    # $x - value corresponding to openssl's X509_REQ structure
	    #
	    # returns: value corresponding to openssl's	X509_NAME structure (0 on failure)

       o   X509_REQ_get_version

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns 'version' value for given X509_REQ object $x.

	    my $rv = Net::SSLeay::X509_REQ_get_version($x);
	    # $x - value corresponding to openssl's X509_REQ structure
	    #
	    # returns: (integer) version e.g. 0	= "version 1"

       o   X509_REQ_set_pubkey

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Sets	public key of given X509_REQ object $x to $pkey.

	    my $rv = Net::SSLeay::X509_REQ_set_pubkey($x, $pkey);
	    # $x - value corresponding to openssl's X509_REQ structure
	    # $pkey - value corresponding to openssl's EVP_PKEY	structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_REQ_set_subject_name

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Sets	subject	name of	given X509_REQ object $x to X509_NAME object
	   $name.

	    my $rv = Net::SSLeay::X509_REQ_set_subject_name($x,	$name);
	    # $x - value corresponding to openssl's X509_REQ structure
	    # $name - value corresponding to openssl's X509_NAME structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_REQ_set_version

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Sets	'version' of given X509_REQ object $x to $version.

	    my $rv = Net::SSLeay::X509_REQ_set_version($x, $version);
	    # $x - value corresponding to openssl's X509_REQ structure
	    # $version - (integer) e.g.	0 = "version 1"
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_REQ_sign

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Sign	X509_REQ object	$x with	private	key $pk	(using digest
	   algorithm $md).

	    my $rv = Net::SSLeay::X509_REQ_sign($x, $pk, $md);
	    # $x - value corresponding to openssl's X509_REQ structure
	    # $pk - value corresponding	to openssl's EVP_PKEY structure	(requestor's private key)
	    # $md - value corresponding	to openssl's EVP_MD structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_REQ_verify

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Verifies X509_REQ object $x using public key	$r (pubkey of
	   requesting party).

	    my $rv = Net::SSLeay::X509_REQ_verify($x, $r);
	    # $x - value corresponding to openssl's X509_REQ structure
	    # $r - value corresponding to openssl's EVP_PKEY structure
	    #
	    # returns: 0 - verify failure, 1 - verify OK, <0 - error

       o   P_X509_REQ_add_extensions

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Adds	one or more X509 extensions to X509_REQ	object $x.

	    my $rv = Net::SSLeay::P_X509_REQ_add_extensions($x,	$nid, $value);
	    # $x - value corresponding to openssl's X509_REQ structure
	    # $nid - NID identifying extension to be set
	    # $value - extension value
	    #
	    # returns: 1 on success, 0 on failure

	   You can set more extensions at once:

	    my $rv = Net::SSLeay::P_X509_REQ_add_extensions($x509_req,
		       &Net::SSLeay::NID_key_usage => 'digitalSignature,keyEncipherment',
		       &Net::SSLeay::NID_basic_constraints => 'CA:FALSE',
		       &Net::SSLeay::NID_ext_key_usage => 'serverAuth,clientAuth',
		       &Net::SSLeay::NID_netscape_cert_type => 'server',
		       &Net::SSLeay::NID_subject_alt_name => 'DNS:s1.com,DNS:s2.com',
		       &Net::SSLeay::NID_crl_distribution_points => 'URI:http://pki.com/crl1,URI:http://pki.com/crl2',
		     );

       o   P_X509_REQ_get_attr

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-0.9.7

	   Returns attribute value for X509_REQ's attribute at index $n.

	    Net::SSLeay::P_X509_REQ_get_attr($req, $n);
	    # $req - value corresponding to openssl's X509_REQ structure
	    # $n - (integer) attribute index
	    #
	    # returns: value corresponding to openssl's	ASN1_STRING structure

       Low level API: X509_CRL_* related functions

       o   X509_CRL_new

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Creates a new X509_CRL structure.

	    my $rv = Net::SSLeay::X509_CRL_new();
	    #
	    # returns: value corresponding to openssl's	X509_CRL structure (0 on failure)

       o   X509_CRL_free

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Free	an allocated X509_CRL structure.

	    Net::SSLeay::X509_CRL_free($x);
	    # $x - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: no return value

       o   X509_CRL_digest

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Computes digest/fingerprint of X509_CRL $data using $type hash
	   function.

	    my $digest_value = Net::SSLeay::X509_CRL_digest($data, $type);
	    # $data - value corresponding to openssl's X509_CRL	structure
	    # $type - value corresponding to openssl's EVP_MD structure	- e.g. got via EVP_get_digestbyname()
	    #
	    # returns: hash value (binary)

	   Example:

	    my $x509_crl
	    my $md = Net::SSLeay::EVP_get_digestbyname("sha1");
	    my $digest_value = Net::SSLeay::X509_CRL_digest($x509_crl, $md);
	    #to	get printable (hex) value of digest use:
	    print "digest=", unpack('H*', $digest_value), "\n";

       o   X509_CRL_get_ext

	   COMPATIBILITY: not available	in Net-SSLeay-1.54 and before

	   Returns X509_EXTENSION from $x509 based on given position/index.

	    my $rv = Net::SSLeay::X509_CRL_get_ext($x509, $index);
	    # $x509 - value corresponding to openssl's X509_CRL	structure
	    # $index - (integer) position/index	of extension within $x509
	    #
	    # returns: value corresponding to openssl's	X509_EXTENSION structure (0 on failure)

       o   X509_CRL_get_ext_by_NID

	   COMPATIBILITY: not available	in Net-SSLeay-1.54 and before

	   Returns X509_EXTENSION from $x509 based on given NID.

	    my $rv = Net::SSLeay::X509_CRL_get_ext_by_NID($x509, $nid, $loc);
	    # $x509 - value corresponding to openssl's X509_CRL	structure
	    # $nid - (integer) NID value
	    # $loc - (integer) position	to start lookup	at
	    #
	    # returns: position/index of extension, negative value on error
	    #	       call Net::SSLeay::X509_CRL_get_ext($x509, $rv) to get the actual	extension

       o   X509_CRL_get_ext_count

	   COMPATIBILITY: not available	in Net-SSLeay-1.54 and before

	   Returns the total number of extensions in X509_CRL object $x.

	    my $rv = Net::SSLeay::X509_CRL_get_ext_count($x);
	    # $x - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: count of	extensions

       o   X509_CRL_get_issuer

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns X509_NAME object corresponding to the issuer	of X509_CRL
	   $x.

	    my $rv = Net::SSLeay::X509_CRL_get_issuer($x);
	    # $x - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: value corresponding to openssl's	X509_NAME structure (0 on failure)

	   See other "X509_NAME_*" functions to	get more info from X509_NAME
	   structure.

       o   X509_CRL_get_lastUpdate

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns 'lastUpdate'	date-time value	of X509_CRL object $x.

	    my $rv = Net::SSLeay::X509_CRL_get_lastUpdate($x);
	    # $x - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: value corresponding to openssl's	ASN1_TIME structure (0 on failure)

       o   X509_CRL_get_nextUpdate

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns 'nextUpdate'	date-time value	of X509_CRL object $x.

	    my $rv = Net::SSLeay::X509_CRL_get_nextUpdate($x);
	    # $x - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: value corresponding to openssl's	ASN1_TIME structure (0 on failure)

       o   X509_CRL_get_version

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns 'version' value of given X509_CRL structure $x.

	    my $rv = Net::SSLeay::X509_CRL_get_version($x);
	    # $x - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: (integer) version

       o   X509_CRL_set_issuer_name

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-0.9.7

	   Sets	the issuer of X509_CRL object $x to X509_NAME object $name.

	    my $rv = Net::SSLeay::X509_CRL_set_issuer_name($x, $name);
	    # $x - value corresponding to openssl's X509_CRL structure
	    # $name - value corresponding to openssl's X509_NAME structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_CRL_set_lastUpdate

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-0.9.7

	   Sets	'lastUpdate' value of X509_CRL object $x to $tm.

	    my $rv = Net::SSLeay::X509_CRL_set_lastUpdate($x, $tm);
	    # $x - value corresponding to openssl's X509_CRL structure
	    # $tm - value corresponding	to openssl's ASN1_TIME structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_CRL_set_nextUpdate

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-0.9.7

	   Sets	'nextUpdate' value of X509_CRL object $x to $tm.

	    my $rv = Net::SSLeay::X509_CRL_set_nextUpdate($x, $tm);
	    # $x - value corresponding to openssl's X509_CRL structure
	    # $tm - value corresponding	to openssl's ASN1_TIME structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_CRL_set_version

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-0.9.7

	   Sets	'version' value	of given X509_CRL structure $x to $version.

	    my $rv = Net::SSLeay::X509_CRL_set_version($x, $version);
	    # $x - value corresponding to openssl's X509_CRL structure
	    # $version - (integer) version number (1 = version 2 CRL)
	    #
	    # returns: 1 on success, 0 on failure

	   Note	that if	you want to use	any X509_CRL extension you need	to set
	   "version 2 CRL" - "Net::SSLeay::X509_CRL_set_version($x, 1)".

       o   X509_CRL_sign

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Sign	X509_CRL object	$x with	private	key $pkey (using digest
	   algorithm $md).

	    my $rv = Net::SSLeay::X509_CRL_sign($x, $pkey, $md);
	    # $x - value corresponding to openssl's X509_CRL structure
	    # $pkey - value corresponding to openssl's EVP_PKEY	structure
	    # $md - value corresponding	to openssl's EVP_MD structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_CRL_sort

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-0.9.7

	   Sorts the data of X509_CRL object so	it will	be written in serial
	   number order.

	    my $rv = Net::SSLeay::X509_CRL_sort($x);
	    # $x - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_CRL_verify

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Verifies X509_CRL object $a using public key	$r (pubkey of issuing
	   CA).

	    my $rv = Net::SSLeay::X509_CRL_verify($a, $r);
	    # $a - value corresponding to openssl's X509_CRL structure
	    # $r - value corresponding to openssl's EVP_PKEY structure
	    #
	    # returns: 0 - verify failure, 1 - verify OK, <0 - error

       o   P_X509_CRL_add_revoked_serial_hex

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-0.9.7

	   Adds	given serial number $serial_hex	to X509_CRL object $crl.

	    Net::SSLeay::P_X509_CRL_add_revoked_serial_hex($crl, $serial_hex, $rev_time, $reason_code, $comp_time);
	    # $crl - value corresponding to openssl's X509_CRL structure
	    # $serial_hex - string (hexadecimal) representation	of serial number
	    # $rev_time	- (revocation time) value corresponding	to openssl's ASN1_TIME structure
	    # $reason_code - [optional]	(integer) reason code (see below) - default 0
	    # $comp_time - [optional] (compromise time)	value corresponding to openssl's ASN1_TIME structure
	    #
	    # returns: no return value

	    reason codes:
	    0 -	unspecified
	    1 -	keyCompromise
	    2 -	CACompromise
	    3 -	affiliationChanged
	    4 -	superseded
	    5 -	cessationOfOperation
	    6 -	certificateHold
	    7 -	removeFromCRL

       o   P_X509_CRL_get_serial

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-0.9.7

	   Returns serial number of X509_CRL object.

	    my $rv = Net::SSLeay::P_X509_CRL_get_serial($crl);
	    # $crl - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: value corresponding to openssl's	ASN1_INTEGER structure (0 on failure)

       o   P_X509_CRL_set_serial

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-0.9.7

	   Sets	serial number of X509_CRL object to $crl_number.

	    my $rv = Net::SSLeay::P_X509_CRL_set_serial($crl, $crl_number);
	    # $crl - value corresponding to openssl's X509_CRL structure
	    # $crl_number - value corresponding	to openssl's ASN1_INTEGER structure
	    #
	    # returns: 1 on success, 0 on failure

       Low level API: X509_EXTENSION_* related functions

       o   X509_EXTENSION_get_critical

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns 'critical' flag of given X509_EXTENSION object $ex.

	    my $rv = Net::SSLeay::X509_EXTENSION_get_critical($ex);
	    # $ex - value corresponding	to openssl's X509_EXTENSION structure
	    #
	    # returns: (integer) 1 - critical, 0 - noncritical

       o   X509_EXTENSION_get_data

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns value (raw data) of X509_EXTENSION object $ne.

	    my $rv = Net::SSLeay::X509_EXTENSION_get_data($ne);
	    # $ne - value corresponding	to openssl's X509_EXTENSION structure
	    #
	    # returns: value corresponding to openssl's	ASN1_OCTET_STRING structure (0 on failure)

	   Note: you can use "P_ASN1_STRING_get" to convert ASN1_OCTET_STRING
	   into	perl scalar variable.

       o   X509_EXTENSION_get_object

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns OID (ASN1_OBJECT) of	X509_EXTENSION object $ne.

	    my $rv = Net::SSLeay::X509_EXTENSION_get_object($ex);
	    # $ex - value corresponding	to openssl's X509_EXTENSION structure
	    #
	    # returns: value corresponding to openssl's	ASN1_OBJECT structure (0 on failure)

       o   X509V3_EXT_print

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns string representation of given X509_EXTENSION object	$ext.

	    Net::SSLeay::X509V3_EXT_print($ext,	$flags,	$utf8_decode);
	    # $ext - value corresponding to openssl's X509_EXTENSION structure
	    # $flags - [optional] (integer) Currently the flag argument	is unused and should be	set to 0
	    # $utf8_decode - [optional]	0 or 1 whether the returned value should be utf8 decoded (default=0)
	    #
	    # returns: no return value

       o   X509V3_EXT_d2i

	   Parses an extension and returns its internal	structure.

	    my $rv = Net::SSLeay::X509V3_EXT_d2i($ext);
	    # $ext - value corresponding to openssl's X509_EXTENSION structure
	    #
	    # returns: pointer ???

       Low level API: X509_NAME_* related functions

       o   X509_NAME_ENTRY_get_data

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Retrieves the field value of	$ne in and ASN1_STRING structure.

	    my $rv = Net::SSLeay::X509_NAME_ENTRY_get_data($ne);
	    # $ne - value corresponding	to openssl's X509_NAME_ENTRY structure
	    #
	    # returns: value corresponding to openssl's	ASN1_STRING structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_NAME_ENTRY_get_object.html>

       o   X509_NAME_ENTRY_get_object

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Retrieves the field name of $ne in and ASN1_OBJECT structure.

	    my $rv = Net::SSLeay::X509_NAME_ENTRY_get_object($ne);
	    # $ne - value corresponding	to openssl's X509_NAME_ENTRY structure
	    #
	    # returns: value corresponding to openssl's	ASN1_OBJECT structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_NAME_ENTRY_get_object.html>

       o   X509_NAME_new

	   COMPATIBILITY: not available	in Net-SSLeay-1.55 and before;
	   requires at least openssl-0.9.5

	   Creates a new X509_NAME structure.  Adds a field whose name is
	   defined by a	string $field. The field value to be added is in
	   $bytes.

	    my $rv = Net::SSLeay::X509_NAME_new();
	    #
	    # returns: value corresponding to openssl's	X509_NAME structure (0 on failure)

       o   X509_NAME_hash

	   COMPATIBILITY: not available	in Net-SSLeay-1.55 and before;
	   requires at least openssl-0.9.5

	   Sort	of a checksum of issuer	name $name.  The result	is not a full
	   hash	(e.g. sha-1), it is kind-of-a-hash truncated to	the size of
	   'unsigned long' (32 bits).  The resulting value might differ	across
	   different openssl versions for the same X509	certificate.

	    my $rv = Net::SSLeay::X509_NAME_hash($name);
	    # $name - value corresponding to openssl's X509_NAME structure
	    #
	    # returns: number representing checksum

       o   X509_NAME_add_entry_by_txt

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-0.9.5

	   Adds	a field	whose name is defined by a string $field. The field
	   value to be added is	in $bytes.

	    my $rv = Net::SSLeay::X509_NAME_add_entry_by_txt($name, $field, $type, $bytes, $len, $loc, $set);
	    # $name - value corresponding to openssl's X509_NAME structure
	    # $field - (string)	field definition (name)	- e.g. "organizationName"
	    # $type - (integer)	type of	data in	$bytes (see below)
	    # $bytes - data to be set
	    # $loc - [optional]	(integer) index	where the new entry is inserted: if it is -1 (default) it is appended
	    # $set - [optional]	(integer) determines how the new type is added.	If it is 0 (default) a new RDN is created
	    #
	    # returns: 1 on success, 0 on failure

	    # values for $type - use constants:
	    &Net::SSLeay::MBSTRING_UTF8	    - $bytes contains utf8 encoded data
	    &Net::SSLeay::MBSTRING_ASC	    - $bytes contains ASCII data

	   Unicode note: when passing non-ascii	(unicode) string in $bytes do
	   not forget to set "$flags = &Net::SSLeay::MBSTRING_UTF8" and	encode
	   the perl $string via	"$bytes	= encode('utf-8', $string)".

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_NAME_add_entry_by_txt.html>

       o   X509_NAME_add_entry_by_NID

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-0.9.5

	   Adds	a field	whose name is defined by a NID $nid. The field value
	   to be added is in $bytes.

	    my $rv = Net::SSLeay::X509_NAME_add_entry_by_NID($name, $nid, $type, $bytes, $len, $loc, $set);
	    # $name - value corresponding to openssl's X509_NAME structure
	    # $nid - (integer) field definition	- NID value
	    # $type - (integer)	type of	data in	$bytes (see below)
	    # $bytes - data to be set
	    # $loc - [optional]	(integer) index	where the new entry is inserted: if it is -1 (default) it is appended
	    # $set - [optional]	(integer) determines how the new type is added.	If it is 0 (default) a new RDN is created
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_NAME_add_entry_by_txt.html>

       o   X509_NAME_add_entry_by_OBJ

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-0.9.5

	   Adds	a field	whose name is defined by a object (OID)	$obj . The
	   field value to be added is in $bytes.

	    my $rv = Net::SSLeay::X509_NAME_add_entry_by_OBJ($name, $obj, $type, $bytes, $len, $loc, $set);
	    # $name - value corresponding to openssl's X509_NAME structure
	    # $obj - field definition -	value corresponding to openssl's ASN1_OBJECT structure
	    # $type - (integer)	type of	data in	$bytes (see below)
	    # $bytes - data to be set
	    # $loc - [optional]	(integer) index	where the new entry is inserted: if it is -1 (default) it is appended
	    # $set - [optional]	(integer) determines how the new type is added.	If it is 0 (default) a new RDN is created
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_NAME_add_entry_by_txt.html>

       o   X509_NAME_cmp

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Compares two	X509_NAME obejcts.

	    my $rv = Net::SSLeay::X509_NAME_cmp($a, $b);
	    # $a - value corresponding to openssl's X509_NAME structure
	    # $b - value corresponding to openssl's X509_NAME structure
	    #
	    # returns: 0 if $a matches $b; non zero otherwise

       o   X509_NAME_digest

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Computes digest/fingerprint of X509_NAME $data using	$type hash
	   function.

	    my $digest_value = Net::SSLeay::X509_NAME_digest($data, $type);
	    # $data - value corresponding to openssl's X509_NAME structure
	    # $type - value corresponding to openssl's EVP_MD structure	- e.g. got via EVP_get_digestbyname()
	    #
	    # returns: hash value (binary)

	    #to	get printable (hex) value of digest use:
	    print unpack('H*', $digest_value);

       o   X509_NAME_entry_count

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns the total number of entries in $name.

	    my $rv = Net::SSLeay::X509_NAME_entry_count($name);
	    # $name - value corresponding to openssl's X509_NAME structure
	    #
	    # returns: (integer) entries count

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_NAME_get_index_by_NID.html>

       o   X509_NAME_get_entry

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Retrieves the X509_NAME_ENTRY from $name corresponding to index
	   $loc. Acceptable values for $loc run	from 0 to
	   "Net::SSLeay::X509_NAME_entry_count($name)- 1". The value returned
	   is an internal pointer which	must not be freed.

	    my $rv = Net::SSLeay::X509_NAME_get_entry($name, $loc);
	    # $name - value corresponding to openssl's X509_NAME structure
	    # $loc - (integer) index of	wanted entry
	    #
	    # returns: value corresponding to openssl's	X509_NAME_ENTRY	structure (0 on	failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_NAME_get_index_by_NID.html>

       o   X509_NAME_print_ex

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns a string with human readable	version	of $name.

	    Net::SSLeay::X509_NAME_print_ex($name, $flags, $utf8_decode);
	    # $name - value corresponding to openssl's X509_NAME structure
	    # $flags - [optional] conversion flags (default XN_FLAG_RFC2253) - see below
	    # $utf8_decode - [optional]	0 or 1 whether the returned value should be utf8 decoded (default=0)
	    #
	    # returns: string representation of	$name

	    #available conversion flags	- use constants:
	    &Net::SSLeay::XN_FLAG_COMPAT
	    &Net::SSLeay::XN_FLAG_DN_REV
	    &Net::SSLeay::XN_FLAG_DUMP_UNKNOWN_FIELDS
	    &Net::SSLeay::XN_FLAG_FN_ALIGN
	    &Net::SSLeay::XN_FLAG_FN_LN
	    &Net::SSLeay::XN_FLAG_FN_MASK
	    &Net::SSLeay::XN_FLAG_FN_NONE
	    &Net::SSLeay::XN_FLAG_FN_OID
	    &Net::SSLeay::XN_FLAG_FN_SN
	    &Net::SSLeay::XN_FLAG_MULTILINE
	    &Net::SSLeay::XN_FLAG_ONELINE
	    &Net::SSLeay::XN_FLAG_RFC2253
	    &Net::SSLeay::XN_FLAG_SEP_COMMA_PLUS
	    &Net::SSLeay::XN_FLAG_SEP_CPLUS_SPC
	    &Net::SSLeay::XN_FLAG_SEP_MASK
	    &Net::SSLeay::XN_FLAG_SEP_MULTILINE
	    &Net::SSLeay::XN_FLAG_SEP_SPLUS_SPC
	    &Net::SSLeay::XN_FLAG_SPC_EQ

	   Most	likely you will	be fine	with default:

	    Net::SSLeay::X509_NAME_print_ex($name, &Net::SSLeay::XN_FLAG_RFC2253);

	   Or you might	want RFC2253-like output without utf8 chars escaping:

	    use	Net::SSLeay qw/XN_FLAG_RFC2253 ASN1_STRFLGS_ESC_MSB/;
	    my $flag_rfc22536_utf8 = (XN_FLAG_RFC2253) & (~ ASN1_STRFLGS_ESC_MSB);
	    my $result = Net::SSLeay::X509_NAME_print_ex($name,	$flag_rfc22536_utf8, 1);

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_NAME_print_ex.html>

       o   X509_NAME_get_text_by_NID

	   Retrieves the text from the first entry in name which matches $nid,
	   if no such entry exists -1 is returned.

	   openssl note: this is a legacy function which has various
	   limitations which makes it of minimal use in	practice. It can only
	   find	the first matching entry and will copy the contents of the
	   field verbatim: this	can be highly confusing	if the target is a
	   multicharacter string type like a BMPString or a UTF8String.

	    Net::SSLeay::X509_NAME_get_text_by_NID($name, $nid);
	    # $name - value corresponding to openssl's X509_NAME structure
	    # $nid - NID value (integer)
	    #
	    # returns: text value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_NAME_get_index_by_NID.html>

       o   X509_NAME_oneline

	   Return an ASCII version of $name.

	    Net::SSLeay::X509_NAME_oneline($name);
	    # $name - value corresponding to openssl's X509_NAME structure
	    #
	    # returns: (string)	ASCII version of $name

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_NAME_print_ex.html>

       o   sk_X509_NAME_free

	   Free	an allocated STACK_OF(X509_NAME) structure.

	    Net::SSLeay::sk_X509_NAME_free($sk);
	    # $sk - value corresponding	to openssl's STACK_OF(X509_NAME) structure
	    #
	    # returns: no return value

       o   sk_X509_NAME_num

	   Return number of items in STACK_OF(X509_NAME)

	    my $rv = Net::SSLeay::sk_X509_NAME_num($sk);
	    # $sk - value corresponding	to openssl's STACK_OF(X509_NAME) structure
	    #
	    # returns: number of items

       o   sk_X509_NAME_value

	   Returns X509_NAME from position $index in STACK_OF(X509_NAME)

	    my $rv = Net::SSLeay::sk_X509_NAME_value($sk, $i);
	    # $sk - value corresponding	to openssl's STACK_OF(X509_NAME) structure
	    # $i - (integer) index/position
	    #
	    # returns: value corresponding to openssl's	X509_NAME structure (0 on failure)

       o   add_file_cert_subjects_to_stack

	   Add a file of certs to a stack. All certs in	$file that are not
	   already in the $stackCAs will be added.

	    my $rv = Net::SSLeay::add_file_cert_subjects_to_stack($stackCAs, $file);
	    # $stackCAs	- value	corresponding to openssl's STACK_OF(X509_NAME) structure
	    # $file - (string) filename
	    #
	    # returns: 1 on success, 0 on failure

       o   add_dir_cert_subjects_to_stack

	   Add a directory of certs to a stack.	All certs in $dir that are not
	   already in the $stackCAs will be added.

	    my $rv = Net::SSLeay::add_dir_cert_subjects_to_stack($stackCAs, $dir);
	    # $stackCAs	- value	corresponding to openssl's STACK_OF(X509_NAME) structure
	    # $dir - (string) the directory to append from. All	files in this directory	will be	examined as potential certs. Any that are acceptable to	SSL_add_dir_cert_subjects_to_stack() that are not already in the stack will be included.
	    #
	    # returns: 1 on success, 0 on failure

       Low level API: X509_STORE_* related functions

       o   X509_STORE_CTX_get_current_cert

	   Returns the certificate in ctx which	caused the error or 0 if no
	   certificate is relevant.

	    my $rv = Net::SSLeay::X509_STORE_CTX_get_current_cert($x509_store_ctx);
	    # $x509_store_ctx -	value corresponding to openssl's X509_STORE_CTX	structure
	    #
	    # returns: value corresponding to openssl's	X509 structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_STORE_CTX_get_error.html>

       o   X509_STORE_CTX_get_error

	   Returns the error code of $ctx.

	    my $rv = Net::SSLeay::X509_STORE_CTX_get_error($x509_store_ctx);
	    # $x509_store_ctx -	value corresponding to openssl's X509_STORE_CTX	structure
	    #
	    # returns: (integer) error code

	   For more info about erro code values	check function
	   "get_verify_result".

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_STORE_CTX_get_error.html>

       o   X509_STORE_CTX_get_error_depth

	   Returns the depth of	the error. This	is a non-negative integer
	   representing	where in the certificate chain the error occurred. If
	   it is zero it occurred in the end entity certificate, one if	it is
	   the certificate which signed	the end	entity certificate and so on.

	    my $rv = Net::SSLeay::X509_STORE_CTX_get_error_depth($x509_store_ctx);
	    # $x509_store_ctx -	value corresponding to openssl's X509_STORE_CTX	structure
	    #
	    # returns: (integer) depth

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_STORE_CTX_get_error.html>

       o   X509_STORE_CTX_get_ex_data

	   Is used to retrieve the information for $idx	from $x509_store_ctx.

	    my $rv = Net::SSLeay::X509_STORE_CTX_get_ex_data($x509_store_ctx, $idx);
	    # $x509_store_ctx -	value corresponding to openssl's X509_STORE_CTX	structure
	    # $idx - (integer) index for application specific data
	    #
	    # returns: pointer to ???

       o   X509_STORE_CTX_set_ex_data

	   Is used to store application	data at	arg for	idx into
	   $x509_store_ctx.

	    my $rv = Net::SSLeay::X509_STORE_CTX_set_ex_data($x509_store_ctx, $idx, $data);
	    # $x509_store_ctx -	value corresponding to openssl's X509_STORE_CTX	structure
	    # $idx - (integer) ???
	    # $data - (pointer)	???
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_STORE_CTX_set_cert

	   Sets	the certificate	to be verified in $x509_store_ctx to $x.

	    Net::SSLeay::X509_STORE_CTX_set_cert($x509_store_ctx, $x);
	    # $x509_store_ctx -	value corresponding to openssl's X509_STORE_CTX	structure
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_STORE_CTX_new.html>

       o   X509_STORE_CTX_set_error

	   Sets	the error code of $ctx to $s. For example it might be used in
	   a verification callback to set an error based on additional checks.

	    Net::SSLeay::X509_STORE_CTX_set_error($x509_store_ctx, $s);
	    # $x509_store_ctx -	value corresponding to openssl's X509_STORE_CTX	structure
	    # $s - (integer) error id
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_STORE_CTX_get_error.html>

       o   X509_STORE_add_cert

	   Adds	X509 certificate $x into the X509_STORE	$store.

	    my $rv = Net::SSLeay::X509_STORE_add_cert($store, $x);
	    # $store - value corresponding to openssl's	X509_STORE structure
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_STORE_add_crl

	   Adds	X509 CRL $x into the X509_STORE	$store.

	    my $rv = Net::SSLeay::X509_STORE_add_crl($store, $x);
	    # $store - value corresponding to openssl's	X509_STORE structure
	    # $x - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_STORE_set1_param

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_STORE_set1_param($store,	$pm);
	    # $store - value corresponding to openssl's	X509_STORE structure
	    # $pm - value corresponding	to openssl's X509_VERIFY_PARAM structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_STORE_set_flags

	    Net::SSLeay::X509_STORE_set_flags($ctx, $flags);
	    # $ctx - value corresponding to openssl's X509_STORE structure
	    # $flags - (unsigned long) flags to	be set (bitmask)
	    #
	    # returns: no return value

	    #to	create $flags value use:
	    0x0001 - X509_V_FLAG_CB_ISSUER_CHECK - Send	issuer+subject checks to verify_cb
	    0x0002 - X509_V_FLAG_USE_CHECK_TIME	- Use check time instead of current time
	    0x0004 - X509_V_FLAG_CRL_CHECK - Lookup CRLs
	    0x0008 - X509_V_FLAG_CRL_CHECK_ALL - Lookup	CRLs for whole chain
	    0x0010 - X509_V_FLAG_IGNORE_CRITICAL - Ignore unhandled critical extensions
	    0x0020 - X509_V_FLAG_X509_STRICT - Disable workarounds for broken certificates
	    0x0040 - X509_V_FLAG_ALLOW_PROXY_CERTS - Enable proxy certificate validation
	    0x0080 - X509_V_FLAG_POLICY_CHECK -	Enable policy checking
	    0x0100 - X509_V_FLAG_EXPLICIT_POLICY - Policy variable require-explicit-policy
	    0x0200 - X509_V_FLAG_INHIBIT_ANY - Policy variable inhibit-any-policy
	    0x0400 - X509_V_FLAG_INHIBIT_MAP - Policy variable inhibit-policy-mapping
	    0x0800 - X509_V_FLAG_NOTIFY_POLICY - Notify	callback that policy is	OK
	    0x1000 - X509_V_FLAG_EXTENDED_CRL_SUPPORT -	Extended CRL features such as indirect CRLs, alternate CRL signing keys
	    0x2000 - X509_V_FLAG_USE_DELTAS - Delta CRL	support
	    0x4000 - X509_V_FLAG_CHECK_SS_SIGNATURE - Check selfsigned CA signature

	    #or	use corresponding constants like
	    $flags = &Net::SSLeay::X509_V_FLAG_CB_ISSUER_CHECK;
	    ...
	    $flags = &Net::SSLeay::X509_V_FLAG_CHECK_SS_SIGNATURE;

       o   X509_STORE_set_purpose

	    Net::SSLeay::X509_STORE_set_purpose($ctx, $purpose);
	    # $ctx - value corresponding to openssl's X509_STORE structure
	    # $purpose - (integer) purpose identifier
	    #
	    # returns: no return value

	   For more details about $purpose identifier check "CTX_set_purpose".

       o   X509_STORE_set_trust

	    Net::SSLeay::X509_STORE_set_trust($ctx, $trust);
	    # $ctx - value corresponding to openssl's X509_STORE structure
	    # $trust - (integer) trust identifier
	    #
	    # returns: no return value

	   For more details about $trust identifier check "CTX_set_trust".

       Low level API: X509_VERIFY_PARAM_* related functions

       o   X509_VERIFY_PARAM_add0_policy

	   Enables policy checking (it is disabled by default) and adds
	   $policy to the acceptable policy set.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_add0_policy($param,	$policy);
	    # $param - value corresponding to openssl's	X509_VERIFY_PARAM structure
	    # $policy -	value corresponding to openssl's ASN1_OBJECT structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_add0_table

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_add0_table($param);
	    # $param - value corresponding to openssl's	X509_VERIFY_PARAM structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_VERIFY_PARAM_clear_flags

	   Clears the flags $flags in param.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_clear_flags($param,	$flags);
	    # $param - value corresponding to openssl's	X509_VERIFY_PARAM structure
	    # $flags - (unsigned long) flags to	be set (bitmask)
	    #
	    # returns: 1 on success, 0 on failure

	   For more details about $flags bitmask see "X509_STORE_set_flags".

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_free

	   Frees up the	X509_VERIFY_PARAM structure.

	    Net::SSLeay::X509_VERIFY_PARAM_free($param);
	    # $param - value corresponding to openssl's	X509_VERIFY_PARAM structure
	    #
	    # returns: no return value

       o   X509_VERIFY_PARAM_get_depth

	   Returns the current verification depth.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_get_depth($param);
	    # $param - value corresponding to openssl's	X509_VERIFY_PARAM structure
	    #
	    # returns: (ineger)	depth

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_get_flags

	   Returns the current verification flags.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_get_flags($param);
	    # $param - value corresponding to openssl's	X509_VERIFY_PARAM structure
	    #
	    # returns: (unsigned long) flags to	be set (bitmask)

	   For more details about returned flags bitmask see
	   "X509_STORE_set_flags".

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_set_flags

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_set_flags($param, $flags);
	    # $param - value corresponding to openssl's	X509_VERIFY_PARAM structure
	    # $flags - (unsigned long) flags to	be set (bitmask)
	    #
	    # returns: 1 on success, 0 on failure

	   For more details about $flags bitmask see "X509_STORE_set_flags".

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_inherit

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_inherit($to, $from);
	    # $to - value corresponding	to openssl's X509_VERIFY_PARAM structure
	    # $from - value corresponding to openssl's X509_VERIFY_PARAM structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_VERIFY_PARAM_lookup

	   Finds X509_VERIFY_PARAM by name.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_lookup($name);
	    # $name - (string) name we want to find
	    #
	    # returns: value corresponding to openssl's	X509_VERIFY_PARAM structure (0 on failure)

       o   X509_VERIFY_PARAM_new

	   Creates a new X509_VERIFY_PARAM structure.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_new();
	    #
	    # returns: value corresponding to openssl's	X509_VERIFY_PARAM structure (0 on failure)

       o   X509_VERIFY_PARAM_set1

	   Sets	the name of X509_VERIFY_PARAM structure	$to to the same	value
	   as the name of X509_VERIFY_PARAM structure $from.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_set1($to, $from);
	    # $to - value corresponding	to openssl's X509_VERIFY_PARAM structure
	    # $from - value corresponding to openssl's X509_VERIFY_PARAM structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_VERIFY_PARAM_set1_name

	   Sets	the name of X509_VERIFY_PARAM structure	$param to $name.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_set1_name($param, $name);
	    # $param - value corresponding to openssl's	X509_VERIFY_PARAM structure
	    # $name - (string) name to be set
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_VERIFY_PARAM_set1_policies

	   Enables policy checking (it is disabled by default) and sets	the
	   acceptable policy set to policies.  Any existing policy set is
	   cleared. The	policies parameter can be 0 to clear an	existing
	   policy set.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_set1_policies($param, $policies);
	    # $param - value corresponding to openssl's	X509_VERIFY_PARAM structure
	    # $policies	- value	corresponding to openssl's STACK_OF(ASN1_OBJECT) structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_set_depth

	   Sets	the maximum verification depth to depth. That is the maximum
	   number of untrusted CA certificates that can	appear in a chain.

	    Net::SSLeay::X509_VERIFY_PARAM_set_depth($param, $depth);
	    # $param - value corresponding to openssl's	X509_VERIFY_PARAM structure
	    # $depth - (integer) depth to be set
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_set_purpose

	   Sets	the verification purpose in $param to $purpose.	This
	   determines the acceptable purpose of	the certificate	chain, for
	   example SSL client or SSL server.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_set_purpose($param,	$purpose);
	    # $param - value corresponding to openssl's	X509_VERIFY_PARAM structure
	    # $purpose - (integer) purpose identifier
	    #
	    # returns: 1 on success, 0 on failure

	   For more details about $purpose identifier check "CTX_set_purpose".

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_set_time

	   Sets	the verification time in $param	to $t. Normally	the current
	   time	is used.

	    Net::SSLeay::X509_VERIFY_PARAM_set_time($param, $t);
	    # $param - value corresponding to openssl's	X509_VERIFY_PARAM structure
	    # $t - (time_t) time in seconds since 1.1.1970
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_set_trust

	   Sets	the trust setting in $param to $trust.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_set_trust($param, $trust);
	    # $param - value corresponding to openssl's	X509_VERIFY_PARAM structure
	    # $trust - (integer) trust identifier
	    #
	    # returns: 1 on success, 0 on failure

	   For more details about $trust identifier check "CTX_set_trust".

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_table_cleanup

	   ??? (more info needed)

	    Net::SSLeay::X509_VERIFY_PARAM_table_cleanup();
	    #
	    # returns: no return value

       Low level API: Cipher (EVP_CIPHER_*) related functions

       o   EVP_get_cipherbyname

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before

	   Returns an EVP_CIPHER structure when	passed a cipher	name.

	    my $rv = Net::SSLeay::EVP_get_cipherbyname($name);
	    # $name - (string) cipher name e.g.	'aes-128-cbc', 'camellia-256-ecb', 'des-ede', ...
	    #
	    # returns: value corresponding to openssl's	EVP_CIPHER structure

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/EVP_EncryptInit.html>

       Low level API: Digest (EVP_MD_*)	related	functions

       o   OpenSSL_add_all_digests

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before

	    Net::SSLeay::OpenSSL_add_all_digests();
	    # no args, no return value

	   http://www.openssl.org/docs/crypto/OpenSSL_add_all_algorithms.html

       o   P_EVP_MD_list_all

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before;
	   requires at least openssl-1.0.0

	   NOTE: Does not exactly correspond to	any low	level API function

	    my $rv = Net::SSLeay::P_EVP_MD_list_all();
	    #
	    # returns: arrayref	- list of available digest names

	   The returned	digest names correspond	to values expected by
	   "EVP_get_digestbyname".

	   Note	that some of the digests are available by default and some
	   only	after calling "OpenSSL_add_all_digests".

       o   EVP_get_digestbyname

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before

	    my $rv = Net::SSLeay::EVP_get_digestbyname($name);
	    # $name - string with digest name
	    #
	    # returns: value corresponding to openssl's	EVP_MD structure

	   The $name param can be:

	    md2
	    md4
	    md5
	    mdc2
	    ripemd160
	    sha
	    sha1
	    sha224
	    sha256
	    sha512
	    whirlpool

	   Or better check the supported digests by calling
	   "P_EVP_MD_list_all".

       o   EVP_MD_type

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before

	    my $rv = Net::SSLeay::EVP_MD_type($md);
	    # $md - value corresponding	to openssl's EVP_MD structure
	    #
	    # returns: the NID (integer) of the	OBJECT IDENTIFIER representing the given message digest

       o   EVP_MD_size

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before

	    my $rv = Net::SSLeay::EVP_MD_size($md);
	    # $md - value corresponding	to openssl's EVP_MD structure
	    #
	    # returns: the size	of the message digest in bytes (e.g. 20	for SHA1)

       o   EVP_MD_CTX_md

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before;
	   requires at least openssl-0.9.7

	    Net::SSLeay::EVP_MD_CTX_md($ctx);
	    # $ctx - value corresponding to openssl's EVP_MD_CTX structure
	    #
	    # returns: value corresponding to openssl's	EVP_MD structure

       o   EVP_MD_CTX_create

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before;
	   requires at least openssl-0.9.7

	   Allocates, initializes and returns a	digest context.

	    my $rv = Net::SSLeay::EVP_MD_CTX_create();
	    #
	    # returns: value corresponding to openssl's	EVP_MD_CTX structure

	   The complete	idea behind EVP_MD_CTX looks like this example:

	     Net::SSLeay::OpenSSL_add_all_digests();

	     my	$md = Net::SSLeay::EVP_get_digestbyname("sha1");
	     my	$ctx = Net::SSLeay::EVP_MD_CTX_create();
	     Net::SSLeay::EVP_DigestInit($ctx, $md);

	     while(my $chunk = get_piece_of_data()) {
	       Net::SSLeay::EVP_DigestUpdate($ctx,$chunk);
	     }

	     my	$result	= Net::SSLeay::EVP_DigestFinal($ctx);
	     Net::SSLeay::EVP_MD_CTX_destroy($ctx);

	     print "digest=", unpack('H*', $result), "\n"; #print hex value

       o   EVP_DigestInit_ex

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before;
	   requires at least openssl-0.9.7

	   Sets	up digest context $ctx to use a	digest $type from ENGINE
	   $impl, $ctx must be initialized before calling this function, type
	   will	typically be supplied by a function such as
	   "EVP_get_digestbyname". If $impl is 0 then the default
	   implementation of digest $type is used.

	    my $rv = Net::SSLeay::EVP_DigestInit_ex($ctx, $type, $impl);
	    # $ctx  - value corresponding to openssl's EVP_MD_CTX structure
	    # $type - value corresponding to openssl's EVP_MD structure
	    # $impl - value corresponding to openssl's ENGINE structure
	    #
	    # returns: 1 for success and 0 for failure

       o   EVP_DigestInit

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before;
	   requires at least openssl-0.9.7

	   Behaves in the same way as "EVP_DigestInit_ex" except the passed
	   context $ctx	does not have to be initialized, and it	always uses
	   the default digest implementation.

	    my $rv = Net::SSLeay::EVP_DigestInit($ctx, $type);
	    # $ctx - value corresponding to openssl's EVP_MD_CTX structure
	    # $type - value corresponding to openssl's EVP_MD structure
	    #
	    # returns: 1 for success and 0 for failure

       o   EVP_MD_CTX_destroy

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before;
	   requires at least openssl-0.9.7

	   Cleans up digest context $ctx and frees up the space	allocated to
	   it, it should be called only	on a context created using
	   "EVP_MD_CTX_create".

	    Net::SSLeay::EVP_MD_CTX_destroy($ctx);
	    # $ctx - value corresponding to openssl's EVP_MD_CTX structure
	    #
	    # returns: no return value

       o   EVP_DigestUpdate

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before;
	   requires at least openssl-0.9.7

	    my $rv = Net::SSLeay::EVP_DigestUpdate($ctx, $data);
	    # $ctx  - value corresponding to openssl's EVP_MD_CTX structure
	    # $data - data to be hashed
	    #
	    # returns: 1 for success and 0 for failure

       o   EVP_DigestFinal_ex

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before;
	   requires at least openssl-0.9.7

	   Retrieves the digest	value from $ctx. After calling
	   "EVP_DigestFinal_ex"	no additional calls to "EVP_DigestUpdate" can
	   be made, but	"EVP_DigestInit_ex" can	be called to initialize	a new
	   digest operation.

	    my $digest_value = Net::SSLeay::EVP_DigestFinal_ex($ctx);
	    # $ctx - value corresponding to openssl's EVP_MD_CTX structure
	    #
	    # returns: hash value (binary)

	    #to	get printable (hex) value of digest use:
	    print unpack('H*', $digest_value);

       o   EVP_DigestFinal

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before;
	   requires at least openssl-0.9.7

	   Similar to "EVP_DigestFinal_ex" except the digest context ctx is
	   automatically cleaned up.

	    my $rv = Net::SSLeay::EVP_DigestFinal($ctx);
	    # $ctx - value corresponding to openssl's EVP_MD_CTX structure
	    #
	    # returns: hash value (binary)

	    #to	get printable (hex) value of digest use:
	    print unpack('H*', $digest_value);

       o   MD2

	   COMPATIBILITY: no supported by default in openssl-1.0.0

	   Computes MD2	from given $data (all data needs to be loaded into
	   memory)

	    my $digest = Net::SSLeay::MD2($data);
	    print "digest(hexadecimal)=", unpack('H*', $digest);

       o   MD4

	   Computes MD4	from given $data (all data needs to be loaded into
	   memory)

	    my $digest = Net::SSLeay::MD4($data);
	    print "digest(hexadecimal)=", unpack('H*', $digest);

       o   MD5

	   Computes MD5	from given $data (all data needs to be loaded into
	   memory)

	    my $digest = Net::SSLeay::MD5($data);
	    print "digest(hexadecimal)=", unpack('H*', $digest);

       o   RIPEMD160

	   Computes RIPEMD160 from given $data (all data needs to be loaded
	   into	memory)

	    my $digest = Net::SSLeay::RIPEMD160($data);
	    print "digest(hexadecimal)=", unpack('H*', $digest);

       o   SHA1

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before

	   Computes SHA1 from given $data (all data needs to be	loaded into
	   memory)

	    my $digest = Net::SSLeay::SHA1($data);
	    print "digest(hexadecimal)=", unpack('H*', $digest);

       o   SHA256

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before;
	   requires at least openssl-0.9.8

	   Computes SHA256 from	given $data (all data needs to be loaded into
	   memory)

	    my $digest = Net::SSLeay::SHA256($data);
	    print "digest(hexadecimal)=", unpack('H*', $digest);

       o   SHA512

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before;
	   requires at least openssl-0.9.8

	   Computes SHA512 from	given $data (all data needs to be loaded into
	   memory)

	    my $digest = Net::SSLeay::SHA512($data);
	    print "digest(hexadecimal)=", unpack('H*', $digest);

       o   EVP_Digest

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before;
	   requires at least openssl-0.9.7

	   Computes "any" digest from given $data (all data needs to be	loaded
	   into	memory)

	    my $md = Net::SSLeay::EVP_get_digestbyname("sha1");	#or any	other algorithm
	    my $digest = Net::SSLeay::EVP_Digest($data,	$md);
	    print "digest(hexadecimal)=", unpack('H*', $digest);

       o   EVP_sha1

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before

	    my $md = Net::SSLeay::EVP_sha1();
	    #
	    # returns: value corresponding to openssl's	EVP_MD structure

       o   EVP_sha256

	   COMPATIBILITY: requires at least openssl-0.9.8

	    my $md = Net::SSLeay::EVP_sha256();
	    #
	    # returns: value corresponding to openssl's	EVP_MD structure

       o   EVP_sha512

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before;
	   requires at least openssl-0.9.8

	    my $md = Net::SSLeay::EVP_sha512();
	    #
	    # returns: value corresponding to openssl's	EVP_MD structure

       o   EVP_add_digest

	    my $rv = Net::SSLeay::EVP_add_digest($digest);
	    # $digest -	value corresponding to openssl's EVP_MD	structure
	    #
	    # returns: 1 on success, 0 otherwise

       Low level API: CIPHER_* related functions

       o   CIPHER_get_name

	   COMPATIBILITY: not available	in Net-SSLeay-1.42 and before

	   Returns name	of the cipher used.

	    my $rv = Net::SSLeay::CIPHER_description($cipher);
	    # $cipher -	value corresponding to openssl's SSL_CIPHER structure
	    #
	    # returns: (string)	cipher name e.g. 'DHE-RSA-AES256-SHA'

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CIPHER_get_name.html>

	   Example:

	    my $ssl_cipher = Net::SSLeay::get_current_cipher($ssl);
	    my $cipher_name = Net::SSLeay::CIPHER_get_name($ssl_cipher);

       o   CIPHER_description

	   Returns a textual description of the	cipher used.

	   ??? (does this function really work?)

	    my $rv = Net::SSLeay::CIPHER_description($cipher, $buf, $size);
	    # $cipher -	value corresponding to openssl's SSL_CIPHER structure
	    # $bufer - (string/buffer) ???
	    # $size - (integer)	???
	    #
	    # returns: (string)	cipher description e.g.	'DHE-RSA-AES256-SHA SSLv3 Kx=DH	Au=RSA Enc=AES(256) Mac=SHA1'

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CIPHER_get_name.html>

       o   CIPHER_get_bits

	   Returns the number of secret	bits used for cipher.

	    my $rv = Net::SSLeay::CIPHER_get_bits($c);
	    # $c - value corresponding to openssl's SSL_CIPHER structure
	    #
	    # returns: (integert) number of secret bits, 0 on error

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CIPHER_get_name.html>

       Low level API: RSA_* related functions

       o   RSA_generate_key

	   Generates a key pair	and returns it in a newly allocated RSA
	   structure.  The pseudo-random number	generator must be seeded prior
	   to calling RSA_generate_key.

	    my $rv = Net::SSLeay::RSA_generate_key($bits, $e, $perl_cb,	$perl_cb_arg);
	    # $bits - (integer)	modulus	size in	bits e.g. 512, 1024, 2048
	    # $e - (integer) public exponent, an odd number, typically 3, 17 or	65537
	    # $perl_cb - [optional] reference to perl callback function
	    # $perl_cb_arg - [optional]	data that will be passed to callback function when invoked
	    #
	    # returns: value corresponding to openssl's	RSA structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/RSA_generate_key.html>

       o   RSA_free

	   Frees the RSA structure and its components. The key is erased
	   before the memory is	returned to the	system.

	    Net::SSLeay::RSA_free($r);
	    # $r - value corresponding to openssl's RSA	structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/RSA_new.html>

       o   RSA_get_key_parameters

	   Returns a list of pointers to BIGNUMs representing the parameters
	   of the key in this order: (n, e, d, p, q, dmp1, dmq1, iqmp)
	   Caution: returned list consists of SV pointers to BIGNUMs, which
	   would need to be blessed as Crypt::OpenSSL::Bignum for further use

	   my (@params)	= RSA_get_key_parameters($r);

       Low level API: BIO_* related functions

       o   BIO_eof

	   Returns 1 if	the BIO	has read EOF, the precise meaning of 'EOF'
	   varies according to the BIO type.

	    my $rv = Net::SSLeay::BIO_eof($s);
	    # $s - value corresponding to openssl's BIO	structure
	    #
	    # returns: 1 if EOF	has been reached 0 otherwise

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/BIO_ctrl.html>

       o   BIO_f_ssl

	   Returns the SSL BIO method. This is a filter	BIO which is a wrapper
	   round the OpenSSL SSL routines adding a BIO 'flavour' to SSL	I/O.

	    my $rv = Net::SSLeay::BIO_f_ssl();
	    #
	    # returns: value corresponding to openssl's	BIO_METHOD structure (0	on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/BIO_f_ssl.html>

       o   BIO_free

	   Frees up a single BIO.

	    my $rv = Net::SSLeay::BIO_free($bio;);
	    # $bio; - value corresponding to openssl's BIO structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/crypto/BIO_new.html>

       o   BIO_new

	   Returns a new BIO using method $type

	    my $rv = Net::SSLeay::BIO_new($type);
	    # $type - value corresponding to openssl's BIO_METHOD structure
	    #
	    # returns: value corresponding to openssl's	BIO structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/BIO_new.html>

       o   BIO_new_buffer_ssl_connect

	   Creates a new BIO chain consisting of a buffering BIO, an SSL BIO
	   (using ctx) and a connect BIO.

	    my $rv = Net::SSLeay::BIO_new_buffer_ssl_connect($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: value corresponding to openssl's	BIO structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/BIO_f_ssl.html>

       o   BIO_new_file

	   Creates a new file BIO with mode $mode the meaning of mode is the
	   same	as the stdio function fopen(). The BIO_CLOSE flag is set on
	   the returned	BIO.

	    my $rv = Net::SSLeay::BIO_new_file($filename, $mode);
	    # $filename	- (string) filename
	    # $mode - (string) opening mode (as	mode by	stdio function fopen)
	    #
	    # returns: value corresponding to openssl's	BIO structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/BIO_s_file.html>

       o   BIO_new_ssl

	   Allocates an	SSL BIO	using SSL_CTX ctx and using client mode	if
	   client is non zero.

	    my $rv = Net::SSLeay::BIO_new_ssl($ctx, $client);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $client -	(integer) 0 or 1 - indicates ssl client	mode
	    #
	    # returns: value corresponding to openssl's	BIO structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/BIO_f_ssl.html>

       o   BIO_new_ssl_connect

	   Creates a new BIO chain consisting of an SSL	BIO (using ctx)
	   followed by a connect BIO.

	    my $rv = Net::SSLeay::BIO_new_ssl_connect($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: value corresponding to openssl's	BIO structure (0 on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/BIO_f_ssl.html>

       o   BIO_pending

	   Return the number of	pending	characters in the BIOs read buffers.

	    my $rv = Net::SSLeay::BIO_pending($s);
	    # $s - value corresponding to openssl's BIO	structure
	    #
	    # returns: the amount of pending data

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/BIO_ctrl.html>

       o   BIO_wpending

	   Return the number of	pending	characters in the BIOs write buffers.

	    my $rv = Net::SSLeay::BIO_wpending($s);
	    # $s - value corresponding to openssl's BIO	structure
	    #
	    # returns: the amount of pending data

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/BIO_ctrl.html>

       o   BIO_read

	   Read	the underlying descriptor.

	    Net::SSLeay::BIO_read($s, $max);
	    # $s - value corresponding to openssl's BIO	structure
	    # $max - [optional]	max. bytes to read (if not specified, the value	32768 is used)
	    #
	    # returns: data

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/BIO_read.html>

       o   BIO_write

	   Attempts to write data from $buffer to BIO $b.

	    my $rv = Net::SSLeay::BIO_write($b,	$buffer);
	    # $b - value corresponding to openssl's BIO	structure
	    # $buffer -	data
	    #
	    # returns: amount of data successfully written
	    #	       or that no data was successfully	read or	written	if the result is 0 or -1
	    #	       or -2 when the operation	is not implemented in the specific BIO type

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/BIO_read.html>

       o   BIO_s_mem

	   Return the memory BIO method	function.

	    my $rv = Net::SSLeay::BIO_s_mem();
	    #
	    # returns: value corresponding to openssl's	BIO_METHOD structure (0	on failure)

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/BIO_s_mem.html>

       o   BIO_ssl_copy_session_id

	   Copies an SSL session id between BIO	chains from and	to. It does
	   this	by locating the	SSL BIOs in each chain and calling
	   SSL_copy_session_id() on the	internal SSL pointer.

	    my $rv = Net::SSLeay::BIO_ssl_copy_session_id($to, $from);
	    # $to - value corresponding	to openssl's BIO structure
	    # $from - value corresponding to openssl's BIO structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/BIO_f_ssl.html>

       o   BIO_ssl_shutdown

	   Closes down an SSL connection on BIO	chain bio. It does this	by
	   locating the	SSL BIO	in the chain and calling SSL_shutdown()	on its
	   internal SSL	pointer.

	    Net::SSLeay::BIO_ssl_shutdown($ssl_bio);
	    # $ssl_bio - value corresponding to	openssl's BIO structure
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/BIO_f_ssl.html>

       Low level API: Server side Server Name Indication (SNI) support

       o   set_tlsext_host_name

	   TBA

       o   get_servername

	   TBA

       o   get_servername_type

	   TBA

       o   CTX_set_tlsext_servername_callback

	   COMPATIBILITY: requires at least OpenSSL 0.9.8f

	   This	function is used in a server to	support	Server side Server
	   Name	Indication (SNI).

	    Net::SSLeay::CTX_set_tlsext_servername_callback($ctx, $code)
	    # $ctx - SSL context
	    # $code - reference	to a subroutine	that will be called when a new connection is being initiated
	    #
	    # returns: no return value
	   On the client side:
	   use set_tlsext_host_name($ssl, $servername) before initiating the SSL connection.

	   On the server side: Set up an additional SSL_CTX() for each
	   different certificate;

	   Add a servername callback to	each SSL_CTX() using
	   CTX_set_tlsext_servername_callback();

	   The callback	function is required to	retrieve the client-supplied
	   servername with get_servername(ssl).	Figure out the right SSL_CTX
	   to go with that host	name, then switch the SSL object to that
	   SSL_CTX with	set_SSL_CTX().

	   Example:

	    # set callback
	    Net::SSLeay::CTX_set_tlsext_servername_callback($ctx,
	       sub {
		 my $ssl = shift;
		 my $h = Net::SSLeay::get_servername($ssl);
		 Net::SSLeay::set_SSL_CTX($ssl,	$hostnames{$h}->{ctx}) if exists $hostnames{$h};
	       } );

	   More	complete example:

	    # ... initialize Net::SSLeay

	    my %hostnames = (
	      'sni1' =>	{ cert=>'sni1.pem', key=>'sni1.key' },
	      'sni2' =>	{ cert=>'sni2.pem', key=>'sni2.key' },
	    );

	    # create a new context for each certificate/key pair
	    for	my $name (keys %hostnames) {
	      $hostnames{$name}->{ctx} = Net::SSLeay::CTX_new or die;
	      Net::SSLeay::CTX_set_cipher_list($hostnames{$name}->{ctx}, 'ALL');
	      Net::SSLeay::set_cert_and_key($hostnames{$name}->{ctx},
	      $hostnames{$name}->{cert}, $hostnames{$name}->{key}) or die;
	    }

	    # create default context
	    my $ctx = Net::SSLeay::CTX_new or die;
	    Net::SSLeay::CTX_set_cipher_list($ctx, 'ALL');
	    Net::SSLeay::set_cert_and_key($ctx,	'cert.pem','key.pem') or die;

	    # set callback
	    Net::SSLeay::CTX_set_tlsext_servername_callback($ctx, sub {
	      my $ssl =	shift;
	      my $h = Net::SSLeay::get_servername($ssl);
	      Net::SSLeay::set_SSL_CTX($ssl, $hostnames{$h}->{ctx}) if exists $hostnames{$h};
	      }	);

	    # ... later

	    $s = Net::SSLeay::new($ctx);
	    Net::SSLeay::set_fd($s, fileno($accepted_socket));
	    Net::SSLeay::accept($s);

       Low level API: NPN (next	protocol negotiation) related functions

       NPN is being replaced with ALPN,	a more recent TLS extension for
       application protocol negotiation	that's in process of being adopted by
       IETF. Please look below for APLN	API description.

       Simple approach for using NPN support looks like	this:

	### client side
	use Net::SSLeay;
	use IO::Socket::INET;

	Net::SSLeay::initialize();
	my $sock = IO::Socket::INET->new(PeerAddr=>'encrypted.google.com:443') or die;
	my $ctx	= Net::SSLeay::CTX_tlsv1_new() or die;
	Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL);
	Net::SSLeay::CTX_set_next_proto_select_cb($ctx,	['http1.1','spdy/2']);
	my $ssl	= Net::SSLeay::new($ctx) or die;
	Net::SSLeay::set_fd($ssl, fileno($sock)) or die;
	Net::SSLeay::connect($ssl);

	warn "client:negotiated=",Net::SSLeay::P_next_proto_negotiated($ssl), "\n";
	warn "client:last_status=", Net::SSLeay::P_next_proto_last_status($ssl), "\n";

	### server side
	use Net::SSLeay;
	use IO::Socket::INET;

	Net::SSLeay::initialize();
	my $ctx	= Net::SSLeay::CTX_tlsv1_new() or die;
	Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL);
	Net::SSLeay::set_cert_and_key($ctx, "t/data/cert.pem", "t/data/key.pem");
	Net::SSLeay::CTX_set_next_protos_advertised_cb($ctx, ['spdy/2','http1.1']);
	my $sock = IO::Socket::INET->new(LocalAddr=>'localhost', LocalPort=>5443, Proto=>'tcp',	Listen=>20) or die;

	while (1) {
	  my $ssl = Net::SSLeay::new($ctx);
	  warn("server:waiting for incoming connection...\n");
	  my $fd = $sock->accept();
	  Net::SSLeay::set_fd($ssl, $fd->fileno);
	  Net::SSLeay::accept($ssl);
	  warn "server:negotiated=",Net::SSLeay::P_next_proto_negotiated($ssl),"\n";
	  my $got = Net::SSLeay::read($ssl);
	  Net::SSLeay::ssl_write_all($ssl, "length=".length($got));
	  Net::SSLeay::free($ssl);
	  $fd->close();
	}
	# check	with: openssl s_client -connect	localhost:5443 -nextprotoneg http/1.1,spdy/2

       Please note that	the selection (negotiation) is performed by client
       side, the server	side simply advertise the list of supported protocols.

       Advanced	approach allows	you to implement your own negotiation
       algorithm.

	#see below documentation for:
	Net::SSleay::CTX_set_next_proto_select_cb($ctx,	$perl_callback_function, $callback_data);
	Net::SSleay::CTX_set_next_protos_advertised_cb($ctx, $perl_callback_function, $callback_data);

       Detection of NPN	support	(works even in older Net::SSLeay versions):

	use Net::SSLeay;

	if (exists &Net::SSLeay::P_next_proto_negotiated) {
	  # do NPN stuff
	}

       o   CTX_set_next_proto_select_cb

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-1.0.1

	   NOTE: You need CTX_set_next_proto_select_cb on client side of SSL
	   connection.

	   Simple usage	- in this case a "common" negotiation algorithm	(as
	   implemented by openssl's function SSL_select_next_proto) is used.

	    $rv	= Net::SSleay::CTX_set_next_proto_select_cb($ctx, $arrayref);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $arrayref	- list of accepted protocols - e.g. ['http1.0',	'http1.1']
	    #
	    # returns: 0 on success, 1 on failure

	   Advanced usage (you probably	do not need this):

	    $rv	= Net::SSleay::CTX_set_next_proto_select_cb($ctx, $perl_callback_function, $callback_data);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $perl_callback_function -	reference to perl function
	    # $callback_data - [optional] data to passed to callback function when invoked
	    #
	    # returns: 0 on success, 1 on failure

	    # where callback function looks like
	    sub	npn_advertised_cb_invoke {
	      my ($ssl,	$arrayref_proto_list_advertised_by_server, $callback_data) = @_;
	      my $status;
	      #	...
	      $status =	1;   #status can be:
			     # 0 - OPENSSL_NPN_UNSUPPORTED
			     # 1 - OPENSSL_NPN_NEGOTIATED
			     # 2 - OPENSSL_NPN_NO_OVERLAP
	      return $status, ['http1.1','spdy/2']; # the callback has to return 2 values
	    }

	   To undefine/clear this callback use:

	    Net::SSleay::CTX_set_next_proto_select_cb($ctx, undef);

       o   CTX_set_next_protos_advertised_cb

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-1.0.1

	   NOTE: You need CTX_set_next_proto_select_cb on server side of SSL
	   connection.

	   Simple usage:

	    $rv	= Net::SSleay::CTX_set_next_protos_advertised_cb($ctx, $arrayref);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $arrayref	- list of advertised protocols - e.g. ['http1.0', 'http1.1']
	    #
	    # returns: 0 on success, 1 on failure

	   Advanced usage (you probably	do not need this):

	    $rv	= Net::SSleay::CTX_set_next_protos_advertised_cb($ctx, $perl_callback_function,	$callback_data);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $perl_callback_function -	reference to perl function
	    # $callback_data - [optional] data to passed to callback function when invoked
	    #
	    # returns: 0 on success, 1 on failure

	    # where callback function looks like
	    sub	npn_advertised_cb_invoke {
	      my ($ssl,	$callback_data)	= @_;
	      #	...
	      return ['http1.1','spdy/2']; # the callback has to return	arrayref
	    }

	   To undefine/clear this callback use:

	    Net::SSleay::CTX_set_next_protos_advertised_cb($ctx, undef);

       o   P_next_proto_negotiated

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-1.0.1

	   Returns the name of negotiated protocol for given SSL connection
	   $ssl.

	    $rv	= Net::SSLeay::P_next_proto_negotiated($ssl)
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (string)	negotiated protocol name (or undef if no negotiation was done or failed	with fatal error)

       o   P_next_proto_last_status

	   COMPATIBILITY: not available	in Net-SSLeay-1.45 and before;
	   requires at least openssl-1.0.1

	   Returns the result of the last negotiation for given	SSL connection
	   $ssl.

	    $rv	= Net::SSLeay::P_next_proto_last_status($ssl)
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (integer) negotiation status
	    #	       0 - OPENSSL_NPN_UNSUPPORTED
	    #	       1 - OPENSSL_NPN_NEGOTIATED
	    #	       2 - OPENSSL_NPN_NO_OVERLAP

       Low level API: ALPN (application	layer protocol negotiation) related
       functions

       Application protocol can	be negotiated via two different	mechanisms
       employing two different TLS extensions: NPN (obsolete) and ALPN
       (recommended).

       The API is rather similar, with slight differences reflecting protocol
       specifics. In particular, with ALPN the protocol	negotiation takes
       place on	server,	while with NPN the client implements the protocol
       negotiation logic.

       With ALPN, the most basic implementation	looks like this:

	### client side
	use Net::SSLeay;
	use IO::Socket::INET;

	Net::SSLeay::initialize();
	my $sock = IO::Socket::INET->new(PeerAddr=>'encrypted.google.com:443') or die;
	my $ctx	= Net::SSLeay::CTX_tlsv1_new() or die;
	Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL);
	Net::SSLeay::CTX_set_alpn_protos($ctx, ['http/1.1', 'http/2.0',	'spdy/3]);
	my $ssl	= Net::SSLeay::new($ctx) or die;
	Net::SSLeay::set_fd($ssl, fileno($sock)) or die;
	Net::SSLeay::connect($ssl);

	warn "client:selected=",Net::SSLeay::P_alpn_selected($ssl), "\n";

	### server side
	use Net::SSLeay;
	use IO::Socket::INET;

	Net::SSLeay::initialize();
	my $ctx	= Net::SSLeay::CTX_tlsv1_new() or die;
	Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL);
	Net::SSLeay::set_cert_and_key($ctx, "t/data/cert.pem", "t/data/key.pem");
	Net::SSLeay::CTX_set_alpn_select_cb($ctx, ['http/1.1', 'http/2.0', 'spdy/3]);
	my $sock = IO::Socket::INET->new(LocalAddr=>'localhost', LocalPort=>5443, Proto=>'tcp',	Listen=>20) or die;

	while (1) {
	  my $ssl = Net::SSLeay::new($ctx);
	  warn("server:waiting for incoming connection...\n");
	  my $fd = $sock->accept();
	  Net::SSLeay::set_fd($ssl, $fd->fileno);
	  Net::SSLeay::accept($ssl);
	  warn "server:selected=",Net::SSLeay::P_alpn_selected($ssl),"\n";
	  my $got = Net::SSLeay::read($ssl);
	  Net::SSLeay::ssl_write_all($ssl, "length=".length($got));
	  Net::SSLeay::free($ssl);
	  $fd->close();
	}
	# check	with: openssl s_client -connect	localhost:5443 -alpn spdy/3,http/1.1

       Advanced	approach allows	you to implement your own negotiation
       algorithm.

	#see below documentation for:
	Net::SSleay::CTX_set_alpn_select_cb($ctx, $perl_callback_function, $callback_data);

       Detection of ALPN support (works	even in	older Net::SSLeay versions):

	use Net::SSLeay;

	if (exists &Net::SSLeay::P_alpn_selected) {
	  # do ALPN stuff
	}

       o   CTX_set_alpn_select_cb

	   COMPATIBILITY: not available	in Net-SSLeay-1.55 and before;
	   requires at least openssl-1.0.2

	   NOTE: You need CTX_set_alpn_select_cb on server side	of TLS
	   connection.

	   Simple usage	- in this case a "common" negotiation algorithm	(as
	   implemented by openssl's function SSL_select_next_proto) is used.

	    $rv	= Net::SSleay::CTX_set_alpn_select_cb($ctx, $arrayref);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $arrayref	- list of accepted protocols - e.g. ['http/2.0', 'http/1.1', 'spdy/3']
	    #
	    # returns: 0 on success, 1 on failure

	   Advanced usage (you probably	do not need this):

	    $rv	= Net::SSleay::CTX_set_alpn_select_cb($ctx, $perl_callback_function, $callback_data);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $perl_callback_function -	reference to perl function
	    # $callback_data - [optional] data to passed to callback function when invoked
	    #
	    # returns: 0 on success, 1 on failure

	    # where callback function looks like
	    sub	alpn_select_cb_invoke {
	      my ($ssl,	$arrayref_proto_list_advertised_by_client, $callback_data) = @_;
	      #	...
	      if ($negotiated) {
		return 'http/2.0';
	      }	else {
		return undef;
	      }
	    }

	   To undefine/clear this callback use:

	    Net::SSleay::CTX_set_alpn_select_cb($ctx, undef);

       o   set_alpn_protos

	   COMPATIBILITY: not available	in Net-SSLeay-1.55 and before;
	   requires at least openssl-1.0.2

	   NOTE: You need set_alpn_protos on client side of TLS	connection.

	   This	adds list of supported application layer protocols to
	   ClientHello message sent by a client.  It advertises	the
	   enumeration of supported protocols:

	    Net::SSLeay::set_alpn_protos($ssl, ['http/1.1', 'http/2.0',	'spdy/3]);
	    # returns 0	on success

       o   CTX_set_alpn_protos

	   COMPATIBILITY: not available	in Net-SSLeay-1.55 and before;
	   requires at least openssl-1.0.2

	   NOTE: You need CTX_set_alpn_protos on client	side of	TLS
	   connection.

	   This	adds list of supported application layer protocols to
	   ClientHello message sent by a client.  It advertises	the
	   enumeration of supported protocols:

	    Net::SSLeay::CTX_set_alpn_protos($ctx, ['http/1.1',	'http/2.0', 'spdy/3]);
	    # returns 0	on success

       o   P_alpn_selected

	   COMPATIBILITY: not available	in Net-SSLeay-1.55 and before;
	   requires at least openssl-1.0.2

	   Returns the name of negotiated protocol for given TLS connection
	   $ssl.

	    $rv	= Net::SSLeay::P_alpn_selected($ssl)
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (string)	negotiated protocol name (or undef if no negotiation was done or failed	with fatal error)

       Low level API: DANE Support

       OpenSSL version 1.0.2 adds preliminary support RFC6698 Domain
       Authentication of Named Entities	(DANE) Transport Layer Association
       within OpenSSL

       o   SSL_get_tlsa_record_byname

	   COMPATIBILITY: DELETED from net-ssleay, since it is not supported
	   by OpenSSL

	   In order to facilitate DANE there is	additional interface,
	   SSL_get_tlsa_record_byname, accepting hostname, port	and socket
	   type	that returns packed TLSA record. In order to make it even
	   easier there	is additional SSL_ctrl function	that calls
	   SSL_get_tlsa_record_byname for you. Latter is recommended for
	   programmers that wish to maintain broader binary compatibility,
	   e.g.	make application work with both	1.0.2 and prior	version	(in
	   which case call to SSL_ctrl with new	code returning error would
	   have	to be ignored when running with	prior version).

	   Net::SSLeay::get_tlsa_record_byname($name, $port, $type);

       Low level API: Other functions

       o   COMP_add_compression_method

	   Adds	the compression	method cm with the identifier id to the	list
	   of available	compression methods.  This list	is globally maintained
	   for all SSL operations within this application.  It cannot be set
	   for specific	SSL_CTX	or SSL objects.

	    my $rv = Net::SSLeay::COMP_add_compression_method($id, $cm);
	    # $id - (integer) compression method id
	    #	    0 to 63:	methods	defined	by the IETF
	    #	    64 to 192:	external party methods assigned	by IANA
	    #	    193	to 255:	reserved for private use
	    #
	    # $cm - value corresponding	to openssl's COMP_METHOD structure
	    #
	    # returns: 0 on success, 1 on failure (check the error queue to find out the reason)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_COMP_add_compression_method.html>

       o   DH_free

	   Frees the DH	structure and its components. The values are erased
	   before the memory is	returned to the	system.

	    Net::SSLeay::DH_free($dh);
	    # $dh - value corresponding	to openssl's DH	structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/DH_new.html>

       o   FIPS_mode_set

	   Enable or disable FIPS mode in a FIPS capable OpenSSL.

	    Net::SSLeay:: FIPS_mode_set($enable);
	    # $enable -	(integer) 1 to enable, 0 to disable

       Low level API: EC related functions

       o   CTX_set_tmp_ecdh

	   TBA

       o   EC_KEY_free

	   TBA

       o   EC_KEY_new_by_curve_name

	   TBA

       o   EC_KEY_generate_key

	   Generates a EC key and returns it in	a newly	allocated EC_KEY
	   structure.  The EC key then can be used to create a PKEY which can
	   be used in calls like X509_set_pubkey.

	    my $key = Net::SSLeay::EVP_PKEY_new();
	    my $ec  = Net::SSLeay::EC_KEY_generate_key($curve);
	    Net::SSLeay::EVP_PKEY_assign_EC_KEY($key,$ec);

	    # $curve - curve name like 'secp521r1' or the matching Id (integer)	of the curve
	    #
	    # returns: value corresponding to openssl's	EC_KEY structure (0 on failure)

	   This	function has no	equivalent in OpenSSL but combines multiple
	   OpenSSL functions for an easier interface.

   Constants
       There are many openssl constants	available in Net::SSLeay. You can use
       them like this:

	use Net::SSLeay;
	print &Net::SSLeay::NID_commonName;
	#or
	print Net::SSLeay::NID_commonName();

       Or you can import them and use:

	use Net::SSLeay	qw/NID_commonName/;
	print &NID_commonName;
	#or
	print NID_commonName();
	#or
	print NID_commonName;

       The constants names are derived from openssl constants, however
       constants starting with "SSL_" prefix have name with "SSL_" part
       stripped	- e.g. openssl's constant "SSL_OP_ALL" is available as
       "Net::SSleay::OP_ALL"

       The list	of all available constant names:

	ASN1_STRFLGS_ESC_CTRL		NID_ext_key_usage		       OP_CRYPTOPRO_TLSEXT_BUG
	ASN1_STRFLGS_ESC_MSB		NID_ext_req			       OP_DONT_INSERT_EMPTY_FRAGMENTS
	ASN1_STRFLGS_ESC_QUOTE		NID_friendlyName		       OP_EPHEMERAL_RSA
	ASN1_STRFLGS_RFC2253		NID_givenName			       OP_LEGACY_SERVER_CONNECT
	CB_ACCEPT_EXIT			NID_hmacWithSHA1		       OP_MICROSOFT_BIG_SSLV3_BUFFER
	CB_ACCEPT_LOOP			NID_id_ad			       OP_MICROSOFT_SESS_ID_BUG
	CB_ALERT			NID_id_ce			       OP_MSIE_SSLV2_RSA_PADDING
	CB_CONNECT_EXIT			NID_id_kp			       OP_NETSCAPE_CA_DN_BUG
	CB_CONNECT_LOOP			NID_id_pbkdf2			       OP_NETSCAPE_CHALLENGE_BUG
	CB_EXIT				NID_id_pe			       OP_NETSCAPE_DEMO_CIPHER_CHANGE_BUG
	CB_HANDSHAKE_DONE		NID_id_pkix			       OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG
	CB_HANDSHAKE_START		NID_id_qt_cps			       OP_NON_EXPORT_FIRST
	CB_LOOP				NID_id_qt_unotice		       OP_NO_COMPRESSION
	CB_READ				NID_idea_cbc			       OP_NO_QUERY_MTU
	CB_READ_ALERT			NID_idea_cfb64			       OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
	CB_WRITE			NID_idea_ecb			       OP_NO_SSLv2
	CB_WRITE_ALERT			NID_idea_ofb64			       OP_NO_SSLv3
	ERROR_NONE			NID_info_access			       OP_NO_TICKET
	ERROR_SSL			NID_initials			       OP_NO_TLSv1
	ERROR_SYSCALL			NID_invalidity_date		       OP_NO_TLSv1_1
	ERROR_WANT_ACCEPT		NID_issuer_alt_name		       OP_NO_TLSv1_2
	ERROR_WANT_CONNECT		NID_keyBag			       OP_PKCS1_CHECK_1
	ERROR_WANT_READ			NID_key_usage			       OP_PKCS1_CHECK_2
	ERROR_WANT_WRITE		NID_localKeyID			       OP_SINGLE_DH_USE
	ERROR_WANT_X509_LOOKUP		NID_localityName		       OP_SINGLE_ECDH_USE
	ERROR_ZERO_RETURN		NID_md2				       OP_SSLEAY_080_CLIENT_DH_BUG
	EVP_PKS_DSA			NID_md2WithRSAEncryption	       OP_SSLREF2_REUSE_CERT_TYPE_BUG
	EVP_PKS_EC			NID_md5				       OP_TLS_BLOCK_PADDING_BUG
	EVP_PKS_RSA			NID_md5WithRSA			       OP_TLS_D5_BUG
	EVP_PKT_ENC			NID_md5WithRSAEncryption	       OP_TLS_ROLLBACK_BUG
	EVP_PKT_EXCH			NID_md5_sha1			       READING
	EVP_PKT_EXP			NID_mdc2			       RECEIVED_SHUTDOWN
	EVP_PKT_SIGN			NID_mdc2WithRSA			       RSA_3
	EVP_PK_DH			NID_ms_code_com			       RSA_F4
	EVP_PK_DSA			NID_ms_code_ind			       R_BAD_AUTHENTICATION_TYPE
	EVP_PK_EC			NID_ms_ctl_sign			       R_BAD_CHECKSUM
	EVP_PK_RSA			NID_ms_efs			       R_BAD_MAC_DECODE
	FILETYPE_ASN1			NID_ms_ext_req			       R_BAD_RESPONSE_ARGUMENT
	FILETYPE_PEM			NID_ms_sgc			       R_BAD_SSL_FILETYPE
	F_CLIENT_CERTIFICATE		NID_name			       R_BAD_SSL_SESSION_ID_LENGTH
	F_CLIENT_HELLO			NID_netscape			       R_BAD_STATE
	F_CLIENT_MASTER_KEY		NID_netscape_base_url		       R_BAD_WRITE_RETRY
	F_D2I_SSL_SESSION		NID_netscape_ca_policy_url	       R_CHALLENGE_IS_DIFFERENT
	F_GET_CLIENT_FINISHED		NID_netscape_ca_revocation_url	       R_CIPHER_TABLE_SRC_ERROR
	F_GET_CLIENT_HELLO		NID_netscape_cert_extension	       R_INVALID_CHALLENGE_LENGTH
	F_GET_CLIENT_MASTER_KEY		NID_netscape_cert_sequence	       R_NO_CERTIFICATE_SET
	F_GET_SERVER_FINISHED		NID_netscape_cert_type		       R_NO_CERTIFICATE_SPECIFIED
	F_GET_SERVER_HELLO		NID_netscape_comment		       R_NO_CIPHER_LIST
	F_GET_SERVER_VERIFY		NID_netscape_data_type		       R_NO_CIPHER_MATCH
	F_I2D_SSL_SESSION		NID_netscape_renewal_url	       R_NO_PRIVATEKEY
	F_READ_N			NID_netscape_revocation_url	       R_NO_PUBLICKEY
	F_REQUEST_CERTIFICATE		NID_netscape_ssl_server_name	       R_NULL_SSL_CTX
	F_SERVER_HELLO			NID_ns_sgc			       R_PEER_DID_NOT_RETURN_A_CERTIFICATE
	F_SSL_CERT_NEW			NID_organizationName		       R_PEER_ERROR
	F_SSL_GET_NEW_SESSION		NID_organizationalUnitName	       R_PEER_ERROR_CERTIFICATE
	F_SSL_NEW			NID_pbeWithMD2AndDES_CBC	       R_PEER_ERROR_NO_CIPHER
	F_SSL_READ			NID_pbeWithMD2AndRC2_CBC	       R_PEER_ERROR_UNSUPPORTED_CERTIFICATE_TYPE
	F_SSL_RSA_PRIVATE_DECRYPT	NID_pbeWithMD5AndCast5_CBC	       R_PUBLIC_KEY_ENCRYPT_ERROR
	F_SSL_RSA_PUBLIC_ENCRYPT	NID_pbeWithMD5AndDES_CBC	       R_PUBLIC_KEY_IS_NOT_RSA
	F_SSL_SESSION_NEW		NID_pbeWithMD5AndRC2_CBC	       R_READ_WRONG_PACKET_TYPE
	F_SSL_SESSION_PRINT_FP		NID_pbeWithSHA1AndDES_CBC	       R_SHORT_READ
	F_SSL_SET_FD			NID_pbeWithSHA1AndRC2_CBC	       R_SSL_SESSION_ID_IS_DIFFERENT
	F_SSL_SET_RFD			NID_pbe_WithSHA1And128BitRC2_CBC       R_UNABLE_TO_EXTRACT_PUBLIC_KEY
	F_SSL_SET_WFD			NID_pbe_WithSHA1And128BitRC4	       R_UNKNOWN_REMOTE_ERROR_TYPE
	F_SSL_USE_CERTIFICATE		NID_pbe_WithSHA1And2_Key_TripleDES_CBC R_UNKNOWN_STATE
	F_SSL_USE_CERTIFICATE_ASN1	NID_pbe_WithSHA1And3_Key_TripleDES_CBC R_X509_LIB
	F_SSL_USE_CERTIFICATE_FILE	NID_pbe_WithSHA1And40BitRC2_CBC	       SENT_SHUTDOWN
	F_SSL_USE_PRIVATEKEY		NID_pbe_WithSHA1And40BitRC4	       SESSION_ASN1_VERSION
	F_SSL_USE_PRIVATEKEY_ASN1	NID_pbes2			       ST_ACCEPT
	F_SSL_USE_PRIVATEKEY_FILE	NID_pbmac1			       ST_BEFORE
	F_SSL_USE_RSAPRIVATEKEY		NID_pkcs			       ST_CONNECT
	F_SSL_USE_RSAPRIVATEKEY_ASN1	NID_pkcs3			       ST_INIT
	F_SSL_USE_RSAPRIVATEKEY_FILE	NID_pkcs7			       ST_OK
	F_WRITE_PENDING			NID_pkcs7_data			       ST_READ_BODY
	GEN_DIRNAME			NID_pkcs7_digest		       ST_READ_HEADER
	GEN_DNS				NID_pkcs7_encrypted		       TLSEXT_STATUSTYPE_ocsp
	GEN_EDIPARTY			NID_pkcs7_enveloped		       VERIFY_CLIENT_ONCE
	GEN_EMAIL			NID_pkcs7_signed		       VERIFY_FAIL_IF_NO_PEER_CERT
	GEN_IPADD			NID_pkcs7_signedAndEnveloped	       VERIFY_NONE
	GEN_OTHERNAME			NID_pkcs8ShroudedKeyBag		       VERIFY_PEER
	GEN_RID				NID_pkcs9			       V_OCSP_CERTSTATUS_GOOD
	GEN_URI				NID_pkcs9_challengePassword	       V_OCSP_CERTSTATUS_REVOKED
	GEN_X400			NID_pkcs9_contentType		       V_OCSP_CERTSTATUS_UNKNOWN
	LIBRESSL_VERSION_NUMBER		NID_pkcs9_countersignature	       WRITING
	MBSTRING_ASC			NID_pkcs9_emailAddress		       X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT
	MBSTRING_BMP			NID_pkcs9_extCertAttributes	       X509_CHECK_FLAG_MULTI_LABEL_WILDCARDS
	MBSTRING_FLAG			NID_pkcs9_messageDigest		       X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS
	MBSTRING_UNIV			NID_pkcs9_signingTime		       X509_CHECK_FLAG_NO_WILDCARDS
	MBSTRING_UTF8			NID_pkcs9_unstructuredAddress	       X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS
	MIN_RSA_MODULUS_LENGTH_IN_BYTES	NID_pkcs9_unstructuredName	       X509_LOOKUP
	MODE_ACCEPT_MOVING_WRITE_BUFFER	NID_private_key_usage_period	       X509_PURPOSE_ANY
	MODE_AUTO_RETRY			NID_rc2_40_cbc			       X509_PURPOSE_CRL_SIGN
	MODE_ENABLE_PARTIAL_WRITE	NID_rc2_64_cbc			       X509_PURPOSE_NS_SSL_SERVER
	MODE_RELEASE_BUFFERS		NID_rc2_cbc			       X509_PURPOSE_OCSP_HELPER
	NID_OCSP_sign			NID_rc2_cfb64			       X509_PURPOSE_SMIME_ENCRYPT
	NID_SMIMECapabilities		NID_rc2_ecb			       X509_PURPOSE_SMIME_SIGN
	NID_X500			NID_rc2_ofb64			       X509_PURPOSE_SSL_CLIENT
	NID_X509			NID_rc4				       X509_PURPOSE_SSL_SERVER
	NID_ad_OCSP			NID_rc4_40			       X509_PURPOSE_TIMESTAMP_SIGN
	NID_ad_ca_issuers		NID_rc5_cbc			       X509_TRUST_COMPAT
	NID_algorithm			NID_rc5_cfb64			       X509_TRUST_EMAIL
	NID_authority_key_identifier	NID_rc5_ecb			       X509_TRUST_OBJECT_SIGN
	NID_basic_constraints		NID_rc5_ofb64			       X509_TRUST_OCSP_REQUEST
	NID_bf_cbc			NID_ripemd160			       X509_TRUST_OCSP_SIGN
	NID_bf_cfb64			NID_ripemd160WithRSA		       X509_TRUST_SSL_CLIENT
	NID_bf_ecb			NID_rle_compression		       X509_TRUST_SSL_SERVER
	NID_bf_ofb64			NID_rsa				       X509_TRUST_TSA
	NID_cast5_cbc			NID_rsaEncryption		       X509_V_FLAG_ALLOW_PROXY_CERTS
	NID_cast5_cfb64			NID_rsadsi			       X509_V_FLAG_CB_ISSUER_CHECK
	NID_cast5_ecb			NID_safeContentsBag		       X509_V_FLAG_CHECK_SS_SIGNATURE
	NID_cast5_ofb64			NID_sdsiCertificate		       X509_V_FLAG_CRL_CHECK
	NID_certBag			NID_secretBag			       X509_V_FLAG_CRL_CHECK_ALL
	NID_certificate_policies	NID_serialNumber		       X509_V_FLAG_EXPLICIT_POLICY
	NID_client_auth			NID_server_auth			       X509_V_FLAG_EXTENDED_CRL_SUPPORT
	NID_code_sign			NID_sha				       X509_V_FLAG_IGNORE_CRITICAL
	NID_commonName			NID_sha1			       X509_V_FLAG_INHIBIT_ANY
	NID_countryName			NID_sha1WithRSA			       X509_V_FLAG_INHIBIT_MAP
	NID_crlBag			NID_sha1WithRSAEncryption	       X509_V_FLAG_NOTIFY_POLICY
	NID_crl_distribution_points	NID_shaWithRSAEncryption	       X509_V_FLAG_POLICY_CHECK
	NID_crl_number			NID_stateOrProvinceName		       X509_V_FLAG_POLICY_MASK
	NID_crl_reason			NID_subject_alt_name		       X509_V_FLAG_TRUSTED_FIRST
	NID_delta_crl			NID_subject_key_identifier	       X509_V_FLAG_USE_CHECK_TIME
	NID_des_cbc			NID_surname			       X509_V_FLAG_USE_DELTAS
	NID_des_cfb64			NID_sxnet			       X509_V_FLAG_X509_STRICT
	NID_des_ecb			NID_time_stamp			       X509_V_OK
	NID_des_ede			NID_title			       XN_FLAG_COMPAT
	NID_des_ede3			NID_undef			       XN_FLAG_DN_REV
	NID_des_ede3_cbc		NID_uniqueIdentifier		       XN_FLAG_DUMP_UNKNOWN_FIELDS
	NID_des_ede3_cfb64		NID_x509Certificate		       XN_FLAG_FN_ALIGN
	NID_des_ede3_ofb64		NID_x509Crl			       XN_FLAG_FN_LN
	NID_des_ede_cbc			NID_zlib_compression		       XN_FLAG_FN_MASK
	NID_des_ede_cfb64		NOTHING				       XN_FLAG_FN_NONE
	NID_des_ede_ofb64		OCSP_RESPONSE_STATUS_INTERNALERROR     XN_FLAG_FN_OID
	NID_des_ofb64			OCSP_RESPONSE_STATUS_MALFORMEDREQUEST  XN_FLAG_FN_SN
	NID_description			OCSP_RESPONSE_STATUS_SIGREQUIRED       XN_FLAG_MULTILINE
	NID_desx_cbc			OCSP_RESPONSE_STATUS_SUCCESSFUL	       XN_FLAG_ONELINE
	NID_dhKeyAgreement		OCSP_RESPONSE_STATUS_TRYLATER	       XN_FLAG_RFC2253
	NID_dnQualifier			OCSP_RESPONSE_STATUS_UNAUTHORIZED      XN_FLAG_SEP_COMMA_PLUS
	NID_dsa				OPENSSL_VERSION_NUMBER		       XN_FLAG_SEP_CPLUS_SPC
	NID_dsaWithSHA			OP_ALL				       XN_FLAG_SEP_MASK
	NID_dsaWithSHA1			OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION   XN_FLAG_SEP_MULTILINE
	NID_dsaWithSHA1_2		OP_CIPHER_SERVER_PREFERENCE	       XN_FLAG_SEP_SPLUS_SPC
	NID_dsa_2			OP_CISCO_ANYCONNECT		       XN_FLAG_SPC_EQ
	NID_email_protect		OP_COOKIE_EXCHANGE
       =head2 INTERNAL ONLY functions (do not use these)

       The following functions are not intended	for use	from outside of
       Net::SSLeay module.  They might be removed, renamed or changed without
       prior notice in future version.

       Simply DO NOT USE THEM!

       o   hello

       o   blength

       o   constant

EXAMPLES
       One very	good example to	look at	is the implementation of "sslcat()" in
       the "SSLeay.pm" file.

       The following is	a simple SSLeay	client (with too little	error checking
       :-(

	   #!/usr/bin/perl
	   use Socket;
	   use Net::SSLeay qw(die_now die_if_ssl_error)	;
	   Net::SSLeay::load_error_strings();
	   Net::SSLeay::SSLeay_add_ssl_algorithms();
	   Net::SSLeay::randomize();

	   ($dest_serv,	$port, $msg) = @ARGV;	   # Read command line
	   $port = getservbyname ($port, 'tcp')	unless $port =~	/^\d+$/;
	   $dest_ip = gethostbyname ($dest_serv);
	   $dest_serv_params  =	sockaddr_in($port, $dest_ip);

	   socket  (S, &AF_INET, &SOCK_STREAM, 0)  or die "socket: $!";
	   connect (S, $dest_serv_params)	   or die "connect: $!";
	   select  (S);	$| = 1;	select (STDOUT);   # Eliminate STDIO buffering

	   # The network connection is now open, lets fire up SSL

	   $ctx	= Net::SSLeay::CTX_new() or die_now("Failed to create SSL_CTX $!");
	   Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL)
		or die_if_ssl_error("ssl ctx set options");
	   $ssl	= Net::SSLeay::new($ctx) or die_now("Failed to create SSL $!");
	   Net::SSLeay::set_fd($ssl, fileno(S));   # Must use fileno
	   $res	= Net::SSLeay::connect($ssl) and die_if_ssl_error("ssl connect");
	   print "Cipher `" . Net::SSLeay::get_cipher($ssl) . "'\n";

	   # Exchange data

	   $res	= Net::SSLeay::write($ssl, $msg);  # Perl knows	how long $msg is
	   die_if_ssl_error("ssl write");
	   CORE::shutdown S, 1;	 # Half	close --> No more output, sends	EOF to server
	   $got	= Net::SSLeay::read($ssl);	   # Perl returns undef	on failure
	   die_if_ssl_error("ssl read");
	   print $got;

	   Net::SSLeay::free ($ssl);		   # Tear down connection
	   Net::SSLeay::CTX_free ($ctx);
	   close S;

       The following is	a simple SSLeay	echo server (non forking):

	   #!/usr/bin/perl -w
	   use Socket;
	   use Net::SSLeay qw(die_now die_if_ssl_error);
	   Net::SSLeay::load_error_strings();
	   Net::SSLeay::SSLeay_add_ssl_algorithms();
	   Net::SSLeay::randomize();

	   $our_ip = "\0\0\0\0"; # Bind	to all interfaces
	   $port = 1235;
	   $sockaddr_template =	'S n a4	x8';
	   $our_serv_params = pack ($sockaddr_template,	&AF_INET, $port, $our_ip);

	   socket (S, &AF_INET,	&SOCK_STREAM, 0)  or die "socket: $!";
	   bind	(S, $our_serv_params)		  or die "bind:	  $!";
	   listen (S, 5)			  or die "listen: $!";
	   $ctx	= Net::SSLeay::CTX_new ()	  or die_now("CTX_new ($ctx): $!");
	   Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL)
		or die_if_ssl_error("ssl ctx set options");

	   # Following will ask	password unless	private	key is not encrypted
	   Net::SSLeay::CTX_use_RSAPrivateKey_file ($ctx, 'plain-rsa.pem',
						    &Net::SSLeay::FILETYPE_PEM);
	   die_if_ssl_error("private key");
	   Net::SSLeay::CTX_use_certificate_file ($ctx,	'plain-cert.pem',
						  &Net::SSLeay::FILETYPE_PEM);
	   die_if_ssl_error("certificate");

	   while (1) {
	       print "Accepting	connections...\n";
	       ($addr =	accept (NS, S))		  or die "accept: $!";
	       select (NS); $| = 1; select (STDOUT);  #	Piping hot!

	       ($af,$client_port,$client_ip) = unpack($sockaddr_template,$addr);
	       @inetaddr = unpack('C4',$client_ip);
	       print "$af connection from " .
	       join ('.', @inetaddr) . ":$client_port\n";

	       # We now	have a network connection, lets	fire up	SSLeay...

	       $ssl = Net::SSLeay::new($ctx)	  or die_now("SSL_new ($ssl): $!");
	       Net::SSLeay::set_fd($ssl, fileno(NS));

	       $err = Net::SSLeay::accept($ssl)	and die_if_ssl_error('ssl accept');
	       print "Cipher `"	. Net::SSLeay::get_cipher($ssl)	. "'\n";

	       # Connected. Exchange some data.

	       $got = Net::SSLeay::read($ssl);	   # Returns undef on fail
	       die_if_ssl_error("ssl read");
	       print "Got `$got' (" . length ($got) . "	chars)\n";

	       Net::SSLeay::write ($ssl, uc ($got)) or die "write: $!";
	       die_if_ssl_error("ssl write");

	       Net::SSLeay::free ($ssl);	   # Tear down connection
	       close NS;
	   }

       Yet another echo	server.	This one runs from "/etc/inetd.conf" so	it
       avoids all the socket code overhead. Only caveat	is opening an rsa key
       file - it had better be without any encryption or else it will not know
       where to	ask for	the password. Note how "STDIN" and "STDOUT" are	wired
       to SSL.

	   #!/usr/bin/perl
	   # /etc/inetd.conf
	   #	ssltst stream tcp nowait root /path/to/server.pl server.pl
	   # /etc/services
	   #	ssltst	       1234/tcp

	   use Net::SSLeay qw(die_now die_if_ssl_error);
	   Net::SSLeay::load_error_strings();
	   Net::SSLeay::SSLeay_add_ssl_algorithms();
	   Net::SSLeay::randomize();

	   chdir '/key/dir' or die "chdir: $!";
	   $| =	1;  # Piping hot!
	   open	LOG, ">>/dev/console" or die "Can't open log file $!";
	   select LOG; print "server.pl	started\n";

	   $ctx	= Net::SSLeay::CTX_new()     or	die_now	"CTX_new ($ctx)	($!)";
	   $ssl	= Net::SSLeay::new($ctx)     or	die_now	"new ($ssl) ($!)";
	   Net::SSLeay::set_options($ssl, &Net::SSLeay::OP_ALL)
		and die_if_ssl_error("ssl set options");

	   # We	get already open network connection from inetd,	now we just
	   # need to attach SSLeay to STDIN and	STDOUT
	   Net::SSLeay::set_rfd($ssl, fileno(STDIN));
	   Net::SSLeay::set_wfd($ssl, fileno(STDOUT));

	   Net::SSLeay::use_RSAPrivateKey_file ($ssl, 'plain-rsa.pem',
						Net::SSLeay::FILETYPE_PEM);
	   die_if_ssl_error("private key");
	   Net::SSLeay::use_certificate_file ($ssl, 'plain-cert.pem',
					      Net::SSLeay::FILETYPE_PEM);
	   die_if_ssl_error("certificate");

	   Net::SSLeay::accept($ssl) and die_if_ssl_err("ssl accept: $!");
	   print "Cipher `" . Net::SSLeay::get_cipher($ssl) . "'\n";

	   $got	= Net::SSLeay::read($ssl);
	   die_if_ssl_error("ssl read");
	   print "Got `$got' ("	. length ($got)	. " chars)\n";

	   Net::SSLeay::write ($ssl, uc($got)) or die "write: $!";
	   die_if_ssl_error("ssl write");

	   Net::SSLeay::free ($ssl);	     # Tear down the connection
	   Net::SSLeay::CTX_free ($ctx);
	   close LOG;

       There are also a	number of example/test programs	in the examples
       directory:

	   sslecho.pl	-  A simple server, not	unlike the one above
	   minicli.pl	-  Implements a	client using low level SSLeay routines
	   sslcat.pl	-  Demonstrates	using high level sslcat	utility	function
	   get_page.pl	-  Is a	utility	for getting html pages from secure servers
	   callback.pl	-  Demonstrates	certificate verification and callback usage
	   stdio_bulk.pl       - Does SSL over Unix pipes
	   ssl-inetd-serv.pl   - SSL server that can be	invoked	from inetd.conf
	   httpd-proxy-snif.pl - Utility that allows you to see	how a browser
				 sends https request to	given server and what reply
				 it gets back (very educative :-)
	   makecert.pl	-  Creates a self signed cert (does not	use this module)

INSTALLATION
       See README and README.* in the distribution directory for installation
       guidance	on a variety of	platforms.

LIMITATIONS
       "Net::SSLeay::read()" uses an internal buffer of	32KB, thus no single
       read will return	more. In practice one read returns much	less, usually
       as much as fits in one network packet. To work around this, you should
       use a loop like this:

	   $reply = '';
	   while ($got = Net::SSLeay::read($ssl)) {
	       last if print_errs('SSL_read');
	       $reply .= $got;
	   }

       Although	there is no built-in limit in "Net::SSLeay::write()", the
       network packet size limitation applies here as well, thus use:

	   $written = 0;

	   while ($written < length($message)) {
	       $written	+= Net::SSLeay::write($ssl, substr($message, $written));
	       last if print_errs('SSL_write');
	   }

       Or alternatively	you can	just use the following convenience functions:

	   Net::SSLeay::ssl_write_all($ssl, $message) or die "ssl write	failure";
	   $got	= Net::SSLeay::ssl_read_all($ssl) or die "ssl read failure";

KNOWN BUGS AND CAVEATS
       An OpenSSL bug CVE-2015-0290 "OpenSSL Multiblock	Corrupted Pointer
       Issue" can cause	POST requests of over 90kB to fail or crash. This bug
       is reported to be fixed in OpenSSL 1.0.2a.

       Autoloader emits	a

	   Argument "xxx" isn't	numeric	in entersub at blib/lib/Net/SSLeay.pm'

       warning if die_if_ssl_error is made autoloadable. If you	figure out
       why, drop me a line.

       Callback	set using "SSL_set_verify()" does not appear to	work. This may
       well be an openssl problem (e.g.	see "ssl/ssl_lib.c" line 1029).	Try
       using "SSL_CTX_set_verify()" instead and	do not be surprised if even
       this stops working in future versions.

       Callback	and certificate	verification stuff is generally	too little
       tested.

       Random numbers are not initialized randomly enough, especially if you
       do not have "/dev/random" and/or	"/dev/urandom" (such as	in Solaris
       platforms - but it's been suggested that	cryptorand daemon from the
       SUNski package solves this). In this case you should investigate	third
       party software that can emulate these devices, e.g. by way of a named
       pipe to some program.

       Another gotcha with random number initialization	is randomness
       depletion. This phenomenon, which has been extensively discussed	in
       OpenSSL,	Apache-SSL, and	Apache-mod_ssl forums, can cause your script
       to block	if you use "/dev/random" or to operate insecurely if you use
       "/dev/urandom". What happens is that when too much randomness is	drawn
       from the	operating system's randomness pool then	randomness can
       temporarily be unavailable. "/dev/random" solves	this problem by
       waiting until enough randomness can be gathered - and this can take a
       long time since blocking	reduces	activity in the	machine	and less
       activity	provides less random events: a vicious circle.	"/dev/urandom"
       solves this dilemma more	pragmatically by simply	returning predictable
       "random"	numbers. Some" /dev/urandom" emulation software	however
       actually	seems to implement "/dev/random" semantics. Caveat emptor.

       I've been pointed to two	such daemons by	Mik Firestone
       <mik@@speed.stdio._com> who has used them on Solaris 8:

       1.  Entropy Gathering Daemon (EGD) at
	   <http://www.lothar.com/tech/crypto/>

       2.  Pseudo-random number	generating daemon (PRNGD) at
	   <http://www.aet.tu-cottbus.de/personen/jaenicke/postfix_tls/prngd.html>

       If you are using	the low	level API functions to communicate with	other
       SSL implementations, you	would do well to call

	   Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL)
		or die_if_ssl_error("ssl ctx set options");

       to cope with some well know bugs	in some	other SSL implementations. The
       high level API functions	always set all known compatibility options.

       Sometimes "sslcat()" (and the high level	HTTPS functions	that build on
       it) is too fast in signaling the	EOF to legacy HTTPS servers. This
       causes the server to return empty page. To work around this problem you
       can set the global variable

	   $Net::SSLeay::slowly	= 1;   # Add sleep so broken servers can keep up

       HTTP/1.1	is not supported. Specifically this module does	not know to
       issue or	serve multiple http requests per connection. This is a serious
       shortcoming, but	using the SSL session cache on your server helps to
       alleviate the CPU load somewhat.

       As of version 1.09 many newer OpenSSL auxiliary functions were added
       (from "REM_AUTOMATICALLY_GENERATED_1_09"	onwards	in "SSLeay.xs").
       Unfortunately I have not	had any	opportunity to test these. Some	of
       them are	trivial	enough that I believe they "just work",	but others
       have rather complex interfaces with function pointers and all. In these
       cases you should	proceed	wit great caution.

       This module defaults to using OpenSSL automatic protocol	negotiation
       code for	automatically detecting	the version of the SSL protocol	that
       the other end talks. With most web servers this works just fine,	but
       once in a while I get complaints	from people that the module does not
       work with some web servers. Usually this	can be solved by explicitly
       setting the protocol version, e.g.

	  $Net::SSLeay::ssl_version = 2;  # Insist on SSLv2
	  $Net::SSLeay::ssl_version = 3;  # Insist on SSLv3
	  $Net::SSLeay::ssl_version = 10; # Insist on TLSv1

       Although	the autonegotiation is nice to have, the SSL standards do not
       formally	specify	any such mechanism. Most of the	world has accepted the
       SSLeay/OpenSSL way of doing it as the de	facto standard.	But for	the
       few that	think differently, you have to explicitly speak	the correct
       version.	This is	not really a bug, but rather a deficiency in the
       standards. If a site refuses to respond or sends	back some nonsensical
       error codes (at the SSL handshake level), try this option before
       mailing me.

       On some systems,	OpenSSL	may be compiled	without	support	for SSLv2.  If
       this is the case, Net::SSLeay will warn if ssl_version has been set to
       2.

       The high	level API returns the certificate of the peer, thus allowing
       one to check what certificate was supplied. However, you	will only be
       able to check the certificate after the fact, i.e. you already sent
       your form data by the time you find out that you	did not	trust them,
       oops.

       So, while being able to know the	certificate after the fact is surely
       useful, the security minded would still choose to do the	connection and
       certificate verification	first and only then exchange data with the
       site. Currently none of the high	level API functions do this, thus you
       would have to program it	using the low level API. A good	place to start
       is to see how the "Net::SSLeay::http_cat()" function is implemented.

       The high	level API functions use	a global file handle "SSLCAT_S"
       internally. This	really should not be a problem because there is	no way
       to interleave the high level API	functions, unless you use threads (but
       threads are not very well supported in perl anyway (as of version
       5.6.1). However,	you may	run into problems if you call undocumented
       internal	functions in an	interleaved fashion. The best solution is to
       "require	Net::SSLeay" in	one thread after all the threads have been
       created.

DIAGNOSTICS
       Random number generator not seeded!!!
	   (W) This warning indicates that "randomize()" was not able to read
	   "/dev/random" or "/dev/urandom", possibly because your system does
	   not have them or they are differently named.	You can	still use SSL,
	   but the encryption will not be as strong.

       open_tcp_connection: destination	host not found:`server'	(port 123)
       ($!)
	   Name	lookup for host	named "server" failed.

       open_tcp_connection: failed `server', 123 ($!)
	   The name was	resolved, but establishing the TCP connection failed.

       msg 123:	1 - error:140770F8:SSL routines:SSL23_GET_SERVER_HELLO:unknown
       proto
	   SSLeay error	string.	The first number (123) is the PID, the second
	   number (1) indicates	the position of	the error message in SSLeay
	   error stack.	 You often see a pile of these messages	as errors
	   cascade.

       msg 123:	1 - error:02001002::lib(2) :func(1) :reason(2)
	   The same as above, but you didn't call load_error_strings() so
	   SSLeay couldn't verbosely explain the error.	You can	still find out
	   what	it means with this command:

	       /usr/local/ssl/bin/ssleay errstr	02001002

       Password	is being asked for private key
	   This	is normal behaviour if your private key	is encrypted. Either
	   you have to supply the password or you have to use an unencrypted
	   private key.	Scan OpenSSL.org for the FAQ that explains how to do
	   this	(or just study examples/makecert.pl which is used during "make
	   test" to do just that).

SECURITY
       You can mitigate	some of	the security vulnerabilities that might	be
       present in your SSL/TLS application:

   BEAST Attack
       http://blogs.cisco.com/security/beat-the-beast-with-tls/
       https://community.qualys.com/blogs/securitylabs/2011/10/17/mitigating-the-beast-attack-on-tls
       http://blog.zoller.lu/2011/09/beast-summary-tls-cbc-countermeasures.html

       The BEAST attack	relies on a weakness in	the way	CBC mode is used in
       SSL/TLS.	 In OpenSSL versions 0.9.6d and	later, the protocol-level
       mitigation is enabled by	default, thus making it	not vulnerable to the
       BEAST attack.

       Solutions:

       o   Compile with	OpenSSL	versions 0.9.6d	or later, which	enables
	   SSL_OP_ALL by default

       o   Ensure SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS is	not enabled (its not
	   enabled by default)

       o   Don't support SSLv2,	SSLv3

       o   Actively control the	ciphers	your server supports with
	   set_cipher_list:

       Net::SSLeay::set_cipher_list($ssl, 'RC4-SHA:HIGH:!ADH');

   Session Resumption
       http://www.openssl.org/docs/ssl/SSL_CTX_set_options.html

       The SSL Labs vulnerability test on your SSL server might	report in red:

       Session resumption      No (IDs assigned	but not	accepted)

       This report is not really bug or	a vulnerability, since the server will
       not accept session resumption requests.	However, you can prevent this
       noise in	the report by disabling	the session cache altogether:
       Net::SSLeay::CTX_set_session_cache_mode($ssl_ctx, 0);

   Secure Renegotiation	and DoS	Attack
       https://community.qualys.com/blogs/securitylabs/2011/10/31/tls-renegotiation-and-denial-of-service-attacks

       This is not a "security flaw," it is more of a DoS vulnerability.

       Solutions:

       o   Do not support SSLv2

       o   Do not set the SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION option

       o   Compile with	OpenSSL	0.9.8m or later

BUGS AND SUPPORT
       Please report any bugs or feature requests to "bug-Net-SSLeay at
       rt.cpan.org", or	through	the web	interface at
       <http://rt.cpan.org/Public/Dist/Display.html?Name=Net-SSLeay>.  I will
       be notified, and	then you'll automatically be notified of progress on
       your bug	as I make changes.

       Subversion access to the	latest source code etc can be obtained at
       <http://alioth.debian.org/projects/net-ssleay>

       The developer mailing list (for people interested in contributing to
       the source code)	can be found at
       <http://lists.alioth.debian.org/mailman/listinfo/net-ssleay-devel>

       You can find documentation for this module with the "perldoc" command.

	   perldoc Net::SSLeay

       You can also look for information at:

       o   AnnoCPAN: Annotated CPAN documentation

	   <http://annocpan.org/dist/Net-SSLeay>

       o   CPAN	Ratings

	   <http://cpanratings.perl.org/d/Net-SSLeay>

       o   Search CPAN

	   <http://search.cpan.org/dist/Net-SSLeay>

       Commercial support for Net::SSLeay may be obtained from

	  Symlabs (netssleay@symlabs.com)
	  Tel: +351-214.222.630
	  Fax: +351-214.222.637

AUTHOR
       Maintained by Mike McCauley and Florian Ragwitz since November 2005

       Originally written by Sampo KellomAxki <sampo@symlabs.com>

COPYRIGHT
       Copyright (c) 1996-2003 Sampo KellomAxki	<sampo@symlabs.com>

       Copyright (C) 2005-2006 Florian Ragwitz <rafl@debian.org>

       Copyright (C) 2005 Mike McCauley	<mikem@airspayce.com>

       All Rights Reserved.

       Distribution and	use of this module is under the	same terms as the
       OpenSSL package itself (i.e. free, but mandatory	attribution; NO
       WARRANTY). Please consult LICENSE file in the root of the Net-SSLeay
       distribution, and also included in this distribution.

       The Authors credit Eric Young and the OpenSSL team with the development
       of the excellent	OpenSSL	library, which this Perl package uses.

       And remember, you, and nobody else but you, are responsible for
       auditing	this module and	OpenSSL	library	for security problems,
       backdoors, and general suitability for your application.

LICENSE
       From version 1.66 onwards, this Net-SSLeay library is issued under the
       "Perl Artistic License 2.0", the	same license as	Perl itself.

       (ignore this line: this is to keep kwalitee happy by saying: Not	GPL)

SEE ALSO
	 Net::SSLeay::Handle			  - File handle	interface
	 ./examples				  - Example servers and	a clients
	 <http://www.openssl.org/>		  - OpenSSL source, documentation, etc
	 openssl-users-request@openssl.org	  - General OpenSSL mailing list
	 <http://www.ietf.org/rfc/rfc2246.txt>	  - TLS	1.0 specification
	 <http://www.w3c.org>			  - HTTP specifications
	 <http://www.ietf.org/rfc/rfc2617.txt>	  - How	to send	password
	 <http://www.lothar.com/tech/crypto/>	  - Entropy Gathering Daemon (EGD)
	 <http://www.aet.tu-cottbus.de/personen/jaenicke/postfix_tls/prngd.html>
				  - pseudo-random number generating daemon (PRNGD)
	 perl(1)
	 perlref(1)
	 perllol(1)
	 perldoc ~openssl/doc/ssl/SSL_CTX_set_verify.pod

perl v5.24.1			  2016-10-31			Net::SSLeay(3)

NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | INSTALLATION | LIMITATIONS | KNOWN BUGS AND CAVEATS | DIAGNOSTICS | SECURITY | BUGS AND SUPPORT | AUTHOR | COPYRIGHT | LICENSE | SEE ALSO

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