1SSL_CTX_SET_CIPHER_LIST(3) OpenSSL SSL_CTX_SET_CIPHER_LIST(3)
2
6 SSL_CTX_set_cipher_list, SSL_set_cipher_list, SSL_CTX_set_ciphersuites,
7 SSL_set_ciphersuites - choose list of available SSL_CIPHERs
8
10 #include <openssl/ssl.h>
11 int SSL_CTX_set_cipher_list(SSL_CTX *ctx, const char *str);
13 int SSL_set_cipher_list(SSL *ssl, const char *str);
14 int SSL_CTX_set_ciphersuites(SSL_CTX *ctx, const char *str);
16 int SSL_set_ciphersuites(SSL *s, const char *str);
17
19 SSL_CTX_set_cipher_list() sets the list of available ciphers (TLSv1.2
20 and below) for ctx using the control string str. The format of the
21 string is described in ciphers(1). The list of ciphers is inherited by
22 all ssl objects created from ctx. This function does not impact TLSv1.3
23 ciphersuites. Use SSL_CTX_set_ciphersuites() to configure those.
24 SSL_set_cipher_list() sets the list of ciphers (TLSv1.2 and below) only
26 for ssl.
27 SSL_CTX_set_ciphersuites() is used to configure the available TLSv1.3
29 ciphersuites for ctx. This is a simple colon (":") separated list of
30 TLSv1.3 ciphersuite names in order of preference. Valid TLSv1.3
31 ciphersuite names are:
32 TLS_AES_128_GCM_SHA256
34 TLS_AES_256_GCM_SHA384
35 TLS_CHACHA20_POLY1305_SHA256
36 TLS_AES_128_CCM_SHA256
37 TLS_AES_128_CCM_8_SHA256
38 An empty list is permissible. The default value for the this setting
40 is:
41 "TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256"
43 SSL_set_ciphersuites() is the same as SSL_CTX_set_ciphersuites() except
45 it configures the ciphersuites for ssl.
46
48 The control string str for SSL_CTX_set_cipher_list() and
49 SSL_set_cipher_list() should be universally usable and not depend on
50 details of the library configuration (ciphers compiled in). Thus no
51 syntax checking takes place. Items that are not recognized, because the
52 corresponding ciphers are not compiled in or because they are mistyped,
53 are simply ignored. Failure is only flagged if no ciphers could be
54 collected at all.
55 It should be noted, that inclusion of a cipher to be used into the list
57 is a necessary condition. On the client side, the inclusion into the
58 list is also sufficient unless the security level excludes it. On the
59 server side, additional restrictions apply. All ciphers have additional
60 requirements. ADH ciphers don't need a certificate, but DH-parameters
61 must have been set. All other ciphers need a corresponding certificate
62 and key.
63 A RSA cipher can only be chosen, when a RSA certificate is available.
65 RSA ciphers using DHE need a certificate and key and additional DH-
66 parameters (see SSL_CTX_set_tmp_dh_callback(3)).
67 A DSA cipher can only be chosen, when a DSA certificate is available.
69 DSA ciphers always use DH key exchange and therefore need DH-parameters
70 (see SSL_CTX_set_tmp_dh_callback(3)).
71 When these conditions are not met for any cipher in the list (e.g. a
73 client only supports export RSA ciphers with an asymmetric key length
74 of 512 bits and the server is not configured to use temporary RSA
75 keys), the "no shared cipher" (SSL_R_NO_SHARED_CIPHER) error is
76 generated and the handshake will fail.
77
79 SSL_CTX_set_cipher_list() and SSL_set_cipher_list() return 1 if any
80 cipher could be selected and 0 on complete failure.
81 SSL_CTX_set_ciphersuites() and SSL_set_ciphersuites() return 1 if the
83 requested ciphersuite list was configured, and 0 otherwise.
84
86 ssl(7), SSL_get_ciphers(3), SSL_CTX_use_certificate(3),
87 SSL_CTX_set_tmp_dh_callback(3), ciphers(1)
88
90 Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
91 Licensed under the OpenSSL license (the "License"). You may not use
93 this file except in compliance with the License. You can obtain a copy
94 in the file LICENSE in the source distribution or at
95 <https://www.openssl.org/source/license.html>.
961.1.1i 2021-07-22 SSL_CTX_SET_CIPHER_LIST(3)