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SSL_ALERT_TYPE_STRING(3)	    OpenSSL	      SSL_ALERT_TYPE_STRING(3)

NAME
       SSL_alert_type_string, SSL_alert_type_string_long,
       SSL_alert_desc_string, SSL_alert_desc_string_long - get textual
       description of alert information

SYNOPSIS
	#include <openssl/ssl.h>

	const char *SSL_alert_type_string(int value);
	const char *SSL_alert_type_string_long(int value);

	const char *SSL_alert_desc_string(int value);
	const char *SSL_alert_desc_string_long(int value);

DESCRIPTION
       SSL_alert_type_string() returns a one letter string indicating the type
       of the alert specified by value.

       SSL_alert_type_string_long() returns a string indicating	the type of
       the alert specified by value.

       SSL_alert_desc_string() returns a two letter string as a	short form
       describing the reason of	the alert specified by value.

       SSL_alert_desc_string_long() returns a string describing	the reason of
       the alert specified by value.

NOTES
       When one	side of	an SSL/TLS communication wants to inform the peer
       about a special situation, it sends an alert. The alert is sent as a
       special message and does	not influence the normal data stream (unless
       its contents results in the communication being canceled).

       A warning alert is sent,	when a non-fatal error condition occurs. The
       "close notify" alert is sent as a warning alert.	Other examples for
       non-fatal errors	are certificate	errors ("certificate expired",
       "unsupported certificate"), for which a warning alert may be sent.
       (The sending party may however decide to	send a fatal error.) The
       receiving side may cancel the connection	on reception of	a warning
       alert on	it discretion.

       Several alert messages must be sent as fatal alert messages as
       specified by the	TLS RFC. A fatal alert always leads to a connection
       abort.

RETURN VALUES
       The following strings can occur for SSL_alert_type_string() or
       SSL_alert_type_string_long():

       "W"/"warning"
       "F"/"fatal"
       "U"/"unknown"
	   This	indicates that no support is available for this	alert type.
	   Probably value does not contain a correct alert message.

       The following strings can occur for SSL_alert_desc_string() or
       SSL_alert_desc_string_long():

       "CN"/"close notify"
	   The connection shall	be closed. This	is a warning alert.

       "UM"/"unexpected	message"
	   An inappropriate message was	received. This alert is	always fatal
	   and should never be observed	in communication between proper
	   implementations.

       "BM"/"bad record	mac"
	   This	alert is returned if a record is received with an incorrect
	   MAC.	This message is	always fatal.

       "DF"/"decompression failure"
	   The decompression function received improper	input (e.g. data that
	   would expand	to excessive length). This message is always fatal.

       "HF"/"handshake failure"
	   Reception of	a handshake_failure alert message indicates that the
	   sender was unable to	negotiate an acceptable	set of security
	   parameters given the	options	available. This	is a fatal error.

       "NC"/"no	certificate"
	   A client, that was asked to send a certificate, does	not send a
	   certificate (SSLv3 only).

       "BC"/"bad certificate"
	   A certificate was corrupt, contained	signatures that	did not	verify
	   correctly, etc

       "UC"/"unsupported certificate"
	   A certificate was of	an unsupported type.

       "CR"/"certificate revoked"
	   A certificate was revoked by	its signer.

       "CE"/"certificate expired"
	   A certificate has expired or	is not currently valid.

       "CU"/"certificate unknown"
	   Some	other (unspecified) issue arose	in processing the certificate,
	   rendering it	unacceptable.

       "IP"/"illegal parameter"
	   A field in the handshake was	out of range or	inconsistent with
	   other fields. This is always	fatal.

       "DC"/"decryption	failed"
	   A TLSCiphertext decrypted in	an invalid way:	either it wasn't an
	   even	multiple of the	block length or	its padding values, when
	   checked, weren't correct. This message is always fatal.

       "RO"/"record overflow"
	   A TLSCiphertext record was received which had a length more than
	   2^14+2048 bytes, or a record	decrypted to a TLSCompressed record
	   with	more than 2^14+1024 bytes. This	message	is always fatal.

       "CA"/"unknown CA"
	   A valid certificate chain or	partial	chain was received, but	the
	   certificate was not accepted	because	the CA certificate could not
	   be located or couldn't be matched with a known, trusted CA.	This
	   message is always fatal.

       "AD"/"access denied"
	   A valid certificate was received, but when access control was
	   applied, the	sender decided not to proceed with negotiation.	 This
	   message is always fatal.

       "DE"/"decode error"
	   A message could not be decoded because some field was out of	the
	   specified range or the length of the	message	was incorrect. This
	   message is always fatal.

       "CY"/"decrypt error"
	   A handshake cryptographic operation failed, including being unable
	   to correctly	verify a signature, decrypt a key exchange, or
	   validate a finished message.

       "ER"/"export restriction"
	   A negotiation not in	compliance with	export restrictions was
	   detected; for example, attempting to	transfer a 1024	bit ephemeral
	   RSA key for the RSA_EXPORT handshake	method.	This message is	always
	   fatal.

       "PV"/"protocol version"
	   The protocol	version	the client has attempted to negotiate is
	   recognized, but not supported. (For example,	old protocol versions
	   might be avoided for	security reasons). This	message	is always
	   fatal.

       "IS"/"insufficient security"
	   Returned instead of handshake_failure when a	negotiation has	failed
	   specifically	because	the server requires ciphers more secure	than
	   those supported by the client. This message is always fatal.

       "IE"/"internal error"
	   An internal error unrelated to the peer or the correctness of the
	   protocol makes it impossible	to continue (such as a memory
	   allocation failure).	This message is	always fatal.

       "US"/"user canceled"
	   This	handshake is being canceled for	some reason unrelated to a
	   protocol failure. If	the user cancels an operation after the
	   handshake is	complete, just closing the connection by sending a
	   close_notify	is more	appropriate. This alert	should be followed by
	   a close_notify. This	message	is generally a warning.

       "NR"/"no	renegotiation"
	   Sent	by the client in response to a hello request or	by the server
	   in response to a client hello after initial handshaking.  Either of
	   these would normally	lead to	renegotiation; when that is not
	   appropriate,	the recipient should respond with this alert; at that
	   point, the original requester can decide whether to proceed with
	   the connection. One case where this would be	appropriate would be
	   where a server has spawned a	process	to satisfy a request; the
	   process might receive security parameters (key length,
	   authentication, etc.) at startup and	it might be difficult to
	   communicate changes to these	parameters after that point. This
	   message is always a warning.

       "UP"/"unknown PSK identity"
	   Sent	by the server to indicate that it does not recognize a PSK
	   identity or an SRP identity.

       "UK"/"unknown"
	   This	indicates that no description is available for this alert
	   type.  Probably value does not contain a correct alert message.

SEE ALSO
       ssl(7), SSL_CTX_set_info_callback(3)

COPYRIGHT
       Copyright 2001-2016 The OpenSSL Project Authors.	All Rights Reserved.

       Licensed	under the OpenSSL license (the "License").  You	may not	use
       this file except	in compliance with the License.	 You can obtain	a copy
       in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.

1.1.1d				  2019-09-10	      SSL_ALERT_TYPE_STRING(3)

NAME | SYNOPSIS | DESCRIPTION | NOTES | RETURN VALUES | SEE ALSO | COPYRIGHT

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