Provided by: libssl-doc_1.1.0g-2ubuntu4_all bug


       SSL_CTX_set_cipher_list, SSL_set_cipher_list - choose list of available SSL_CIPHERs


        #include <openssl/ssl.h>

        int SSL_CTX_set_cipher_list(SSL_CTX *ctx, const char *str);
        int SSL_set_cipher_list(SSL *ssl, const char *str);


       SSL_CTX_set_cipher_list() sets the list of available ciphers for ctx using the control
       string str. The format of the string is described in ciphers(1). The list of ciphers is
       inherited by all ssl objects created from ctx.

       SSL_set_cipher_list() sets the list of ciphers only for ssl.


       The control string str should be universally usable and not depend on details of the
       library configuration (ciphers compiled in). Thus no syntax checking takes place. Items
       that are not recognized, because the corresponding ciphers are not compiled in or because
       they are mistyped, are simply ignored. Failure is only flagged if no ciphers could be
       collected at all.

       It should be noted, that inclusion of a cipher to be used into the list is a necessary
       condition. On the client side, the inclusion into the list is also sufficient unless the
       security level excludes it. On the server side, additional restrictions apply. All ciphers
       have additional requirements.  ADH ciphers don't need a certificate, but DH-parameters
       must have been set.  All other ciphers need a corresponding certificate and key.

       A RSA cipher can only be chosen, when a RSA certificate is available.  RSA ciphers using
       DHE need a certificate and key and additional DH-parameters (see

       A DSA cipher can only be chosen, when a DSA certificate is available.  DSA ciphers always
       use DH key exchange and therefore need DH-parameters (see SSL_CTX_set_tmp_dh_callback(3)).

       When these conditions are not met for any cipher in the list (e.g. a client only supports
       export RSA ciphers with an asymmetric key length of 512 bits and the server is not
       configured to use temporary RSA keys), the "no shared cipher" (SSL_R_NO_SHARED_CIPHER)
       error is generated and the handshake will fail.


       SSL_CTX_set_cipher_list() and SSL_set_cipher_list() return 1 if any cipher could be
       selected and 0 on complete failure.


       ssl(3), SSL_get_ciphers(3), SSL_CTX_use_certificate(3), SSL_CTX_set_tmp_dh_callback(3),


       Copyright 2000-2016 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 <>.