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SSL(7)				    OpenSSL				SSL(7)

       ssl - OpenSSL SSL/TLS library

       See the individual manual pages for details.

       The OpenSSL ssl library implements several versions of the Secure
       Sockets Layer, Transport	Layer Security,	and Datagram Transport Layer
       Security	protocols.  This page gives a brief overview of	the extensive
       API and data types provided by the library.

       An SSL_CTX object is created as a framework to establish	TLS/SSL
       enabled connections (see	SSL_CTX_new(3)).  Various options regarding
       certificates, algorithms	etc. can be set	in this	object.

       When a network connection has been created, it can be assigned to an
       SSL object. After the SSL object	has been created using SSL_new(3),
       SSL_set_fd(3) or	SSL_set_bio(3) can be used to associate	the network
       connection with the object.

       When the	TLS/SSL	handshake is performed using SSL_accept(3) or
       SSL_connect(3) respectively.  SSL_read_ex(3), SSL_read(3),
       SSL_write_ex(3) and SSL_write(3)	are used to read and write data	on the
       TLS/SSL connection.  SSL_shutdown(3) can	be used	to shut	down the
       TLS/SSL connection.

       Here are	some of	the main data structures in the	library.

       SSL_METHOD (SSL Method)
	   This	is a dispatch structure	describing the internal	ssl library
	   methods/functions which implement the various protocol versions
	   (SSLv3 TLSv1, ...). It's needed to create an	SSL_CTX.

       SSL_CIPHER (SSL Cipher)
	   This	structure holds	the algorithm information for a	particular
	   cipher which	are a core part	of the SSL/TLS protocol. The available
	   ciphers are configured on a SSL_CTX basis and the actual ones used
	   are then part of the	SSL_SESSION.

       SSL_CTX (SSL Context)
	   This	is the global context structure	which is created by a server
	   or client once per program life-time	and which holds	mainly default
	   values for the SSL structures which are later created for the

       SSL_SESSION (SSL	Session)
	   This	is a structure containing the current TLS/SSL session details
	   for a connection: SSL_CIPHERs, client and server certificates,
	   keys, etc.

       SSL (SSL	Connection)
	   This	is the main SSL/TLS structure which is created by a server or
	   client per established connection. This actually is the core
	   structure in	the SSL	API.  At run-time the application usually
	   deals with this structure which has links to	mostly all other

       Currently the OpenSSL ssl library provides the following	C header files
       containing the prototypes for the data structures and functions:

	   This	is the common header file for the SSL/TLS API.	Include	it
	   into	your program to	make the API of	the ssl	library	available. It
	   internally includes both more private SSL headers and headers from
	   the crypto library.	Whenever you need hard-core details on the
	   internals of	the SSL	API, look inside this header file.  This file
	   also	includes the others listed below.

	   Unused. Present for backwards compatibility only.

	   This	is the sub header file dealing with the	SSLv3 protocol only.

	   This	is the sub header file dealing with the	TLSv1 protocol only.

       Copyright 2000-2018 The OpenSSL Project Authors.	All Rights Reserved.

       Licensed	under the Apache License 2.0 (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

3.0.0-alpha6			  2020-08-06				SSL(7)


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