xref: /openssl/doc/man3/SSL_CIPHER_get_name.pod (revision 7ed6de99)
1=pod
2
3=head1 NAME
4
5SSL_CIPHER_get_name,
6SSL_CIPHER_standard_name,
7OPENSSL_cipher_name,
8SSL_CIPHER_get_bits,
9SSL_CIPHER_get_version,
10SSL_CIPHER_description,
11SSL_CIPHER_get_cipher_nid,
12SSL_CIPHER_get_digest_nid,
13SSL_CIPHER_get_handshake_digest,
14SSL_CIPHER_get_kx_nid,
15SSL_CIPHER_get_auth_nid,
16SSL_CIPHER_is_aead,
17SSL_CIPHER_find,
18SSL_CIPHER_get_id,
19SSL_CIPHER_get_protocol_id
20- get SSL_CIPHER properties
21
22=head1 SYNOPSIS
23
24 #include <openssl/ssl.h>
25
26 const char *SSL_CIPHER_get_name(const SSL_CIPHER *cipher);
27 const char *SSL_CIPHER_standard_name(const SSL_CIPHER *cipher);
28 const char *OPENSSL_cipher_name(const char *stdname);
29 int SSL_CIPHER_get_bits(const SSL_CIPHER *cipher, int *alg_bits);
30 const char *SSL_CIPHER_get_version(const SSL_CIPHER *cipher);
31 char *SSL_CIPHER_description(const SSL_CIPHER *cipher, char *buf, int size);
32 int SSL_CIPHER_get_cipher_nid(const SSL_CIPHER *c);
33 int SSL_CIPHER_get_digest_nid(const SSL_CIPHER *c);
34 const EVP_MD *SSL_CIPHER_get_handshake_digest(const SSL_CIPHER *c);
35 int SSL_CIPHER_get_kx_nid(const SSL_CIPHER *c);
36 int SSL_CIPHER_get_auth_nid(const SSL_CIPHER *c);
37 int SSL_CIPHER_is_aead(const SSL_CIPHER *c);
38 const SSL_CIPHER *SSL_CIPHER_find(SSL *ssl, const unsigned char *ptr);
39 uint32_t SSL_CIPHER_get_id(const SSL_CIPHER *c);
40 uint32_t SSL_CIPHER_get_protocol_id(const SSL_CIPHER *c);
41
42=head1 DESCRIPTION
43
44SSL_CIPHER_get_name() returns a pointer to the name of B<cipher>. If the
45B<cipher> is NULL, it returns "(NONE)".
46
47SSL_CIPHER_standard_name() returns a pointer to the standard RFC name of
48B<cipher>. If the B<cipher> is NULL, it returns "(NONE)". If the B<cipher>
49has no standard name, it returns B<NULL>. If B<cipher> was defined in both
50SSLv3 and TLS, it returns the TLS name.
51
52OPENSSL_cipher_name() returns a pointer to the OpenSSL name of B<stdname>.
53If the B<stdname> is NULL, or B<stdname> has no corresponding OpenSSL name,
54it returns "(NONE)". Where both exist, B<stdname> should be the TLS name rather
55than the SSLv3 name.
56
57SSL_CIPHER_get_bits() returns the number of secret bits used for B<cipher>.
58If B<cipher> is NULL, 0 is returned.
59
60SSL_CIPHER_get_version() returns string which indicates the SSL/TLS protocol
61version that first defined the cipher.  It returns "(NONE)" if B<cipher> is NULL.
62
63SSL_CIPHER_get_cipher_nid() returns the cipher NID corresponding to B<c>.
64If there is no cipher (e.g. for cipher suites with no encryption) then
65B<NID_undef> is returned.
66
67SSL_CIPHER_get_digest_nid() returns the digest NID corresponding to the MAC
68used by B<c> during record encryption/decryption. If there is no digest (e.g.
69for AEAD cipher suites) then B<NID_undef> is returned.
70
71SSL_CIPHER_get_handshake_digest() returns an EVP_MD for the digest used during
72the SSL/TLS handshake when using the SSL_CIPHER B<c>. Note that this may be
73different to the digest used to calculate the MAC for encrypted records.
74
75SSL_CIPHER_get_kx_nid() returns the key exchange NID corresponding to the method
76used by B<c>. If there is no key exchange, then B<NID_undef> is returned.
77If any appropriate key exchange algorithm can be used (as in the case of TLS 1.3
78cipher suites) B<NID_kx_any> is returned. Examples (not comprehensive):
79
80 NID_kx_rsa
81 NID_kx_ecdhe
82 NID_kx_dhe
83 NID_kx_psk
84
85SSL_CIPHER_get_auth_nid() returns the authentication NID corresponding to the method
86used by B<c>. If there is no authentication, then B<NID_undef> is returned.
87If any appropriate authentication algorithm can be used (as in the case of
88TLS 1.3 cipher suites) B<NID_auth_any> is returned. Examples (not comprehensive):
89
90 NID_auth_rsa
91 NID_auth_ecdsa
92 NID_auth_psk
93
94SSL_CIPHER_is_aead() returns 1 if the cipher B<c> is AEAD (e.g. GCM or
95ChaCha20/Poly1305), and 0 if it is not AEAD.
96
97SSL_CIPHER_find() returns a B<SSL_CIPHER> structure which has the cipher ID stored
98in B<ptr>. The B<ptr> parameter is a two element array of B<char>, which stores the
99two-byte TLS cipher ID (as allocated by IANA) in network byte order. This parameter
100is usually retrieved from a TLS packet by using functions like
101L<SSL_client_hello_get0_ciphers(3)>.  SSL_CIPHER_find() returns NULL if an
102error occurs or the indicated cipher is not found.
103
104SSL_CIPHER_get_id() returns the OpenSSL-specific ID of the given cipher B<c>. That ID is
105not the same as the IANA-specific ID.
106
107SSL_CIPHER_get_protocol_id() returns the two-byte ID used in the TLS protocol of the given
108cipher B<c>.
109
110SSL_CIPHER_description() returns a textual description of the cipher used
111into the buffer B<buf> of length B<len> provided.  If B<buf> is provided, it
112must be at least 128 bytes. If B<buf> is NULL it will be allocated using
113OPENSSL_malloc().  If the provided buffer is too small, or the allocation fails,
114B<NULL> is returned.
115
116The string returned by SSL_CIPHER_description() consists of several fields
117separated by whitespace:
118
119=over 4
120
121=item <ciphername>
122
123Textual representation of the cipher name.
124
125=item <protocol version>
126
127The minimum protocol version that the ciphersuite supports, such as B<TLSv1.2>.
128Note that this is not always the same as the protocol version in which the
129ciphersuite was first defined because some ciphersuites are backwards compatible
130with earlier protocol versions.
131
132=item Kx=<key exchange>
133
134Key exchange method such as B<RSA>, B<ECDHE>, etc.
135
136=item Au=<authentication>
137
138Authentication method such as B<RSA>, B<None>, etc.. None is the
139representation of anonymous ciphers.
140
141=item Enc=<symmetric encryption method>
142
143Encryption method, with number of secret bits, such as B<AESGCM(128)>.
144
145=item Mac=<message authentication code>
146
147Message digest, such as B<SHA256>.
148
149=back
150
151Some examples for the output of SSL_CIPHER_description():
152
153 ECDHE-RSA-AES256-GCM-SHA256 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AESGCM(256) Mac=AEAD
154 RSA-PSK-AES256-CBC-SHA384 TLSv1.0 Kx=RSAPSK   Au=RSA  Enc=AES(256)  Mac=SHA384
155
156=head1 RETURN VALUES
157
158SSL_CIPHER_get_name(), SSL_CIPHER_standard_name(), OPENSSL_cipher_name(),
159SSL_CIPHER_get_version() and SSL_CIPHER_description() return the corresponding
160value in a NUL-terminated string for a specific cipher or "(NONE)"
161if the cipher is not found.
162
163SSL_CIPHER_get_bits() returns a positive integer representing the number of
164secret bits or 0 if an error occurred.
165
166SSL_CIPHER_get_cipher_nid(), SSL_CIPHER_get_digest_nid(),
167SSL_CIPHER_get_kx_nid() and SSL_CIPHER_get_auth_nid() return the NID value or
168B<NID_undef> if an error occurred.
169
170SSL_CIPHER_get_handshake_digest() returns a valid B<EVP_MD> structure or NULL
171if an error occurred.
172
173SSL_CIPHER_is_aead() returns 1 if the cipher is AEAD or 0 otherwise.
174
175SSL_CIPHER_find() returns a valid B<SSL_CIPHER> structure or NULL if an error
176occurred.
177
178SSL_CIPHER_get_id() returns a 4-byte integer representing the OpenSSL-specific ID.
179
180SSL_CIPHER_get_protocol_id() returns a 2-byte integer representing the TLS
181protocol-specific ID.
182
183=head1 SEE ALSO
184
185L<ssl(7)>, L<SSL_get_current_cipher(3)>,
186L<SSL_get_ciphers(3)>, L<openssl-ciphers(1)>
187
188=head1 HISTORY
189
190The SSL_CIPHER_get_version() function was updated to always return the
191correct protocol string in OpenSSL 1.1.0.
192
193The SSL_CIPHER_description() function was changed to return B<NULL> on error,
194rather than a fixed string, in OpenSSL 1.1.0.
195
196The SSL_CIPHER_get_handshake_digest() function was added in OpenSSL 1.1.1.
197
198The SSL_CIPHER_standard_name() function was globally available in OpenSSL 1.1.1.
199 Before OpenSSL 1.1.1, tracing (B<enable-ssl-trace> argument to Configure) was
200required to enable this function.
201
202The OPENSSL_cipher_name() function was added in OpenSSL 1.1.1.
203
204=head1 COPYRIGHT
205
206Copyright 2000-2024 The OpenSSL Project Authors. All Rights Reserved.
207
208Licensed under the Apache License 2.0 (the "License").  You may not use
209this file except in compliance with the License.  You can obtain a copy
210in the file LICENSE in the source distribution or at
211L<https://www.openssl.org/source/license.html>.
212
213=cut
214