NAME¶

SYNOPSIS¶

 #include <openssl/ssl.h>

 const char *SSL_CIPHER_get_name(const SSL_CIPHER *cipher);
 int SSL_CIPHER_get_bits(const SSL_CIPHER *cipher, int *alg_bits);
 char *SSL_CIPHER_get_version(const SSL_CIPHER *cipher);
 char *SSL_CIPHER_description(const SSL_CIPHER *cipher, char *buf, int size);
 int SSL_CIPHER_get_cipher_nid(const SSL_CIPHER *c);
 int SSL_CIPHER_get_digest_nid(const SSL_CIPHER *c);
 int SSL_CIPHER_get_kx_nid(const SSL_CIPHER *c);
 int SSL_CIPHER_get_auth_nid(const SSL_CIPHER *c);
 int SSL_CIPHER_is_aead(const SSL_CIPHER *c);

DESCRIPTION¶

SSL_CIPHER_get_bits() returns the number of secret bits used for cipher. If cipher is NULL, 0 is returned.

SSL_CIPHER_get_version() returns string which indicates the SSL/TLS protocol version that first defined the cipher. It returns "(NONE)" if cipher is NULL.

SSL_CIPHER_get_cipher_nid() returns the cipher NID corresponding to c. If there is no cipher (e.g. for ciphersuites with no encryption) then NID_undef is returned.

SSL_CIPHER_get_digest_nid() returns the digest NID corresponding to the MAC used by c. If there is no digest (e.g. for AEAD ciphersuites) then NID_undef is returned.

SSL_CIPHER_get_kx_nid() returns the key exchange NID corresponding to the method used by c. If there is no key exchange, then NID_undef is returned. Examples (not comprehensive):

 NID_kx_rsa
 NID_kx_ecdhe
 NID_kx_dhe
 NID_kx_psk

SSL_CIPHER_get_auth_nid() returns the authentication NID corresponding to the method used by c. If there is no authentication, then NID_undef is returned. Examples (not comprehensive):

 NID_auth_rsa
 NID_auth_ecdsa
 NID_auth_psk

SSL_CIPHER_is_aead() returns 1 if the cipher c is AEAD (e.g. GCM or ChaCha20/Poly1305), and 0 if it is not AEAD.

SSL_CIPHER_description() returns a textual description of the cipher used into the buffer buf of length len provided. If buf is provided, it must be at least 128 bytes, otherwise a buffer will be allocated using OPENSSL_malloc(). If the provided buffer is too small, or the allocation fails, NULL is returned.

The string returned by SSL_CIPHER_description() consists of several fields separated by whitespace:

<ciphername>

Textual representation of the cipher name.

<protocol version>

Protocol version, such as TLSv1.2, when the cipher was first defined.

Kx=<key exchange>

Key exchange method such as RSA, ECDHE, etc.

Au=<authentication>

Authentication method such as RSA, None, etc.. None is the representation of anonymous ciphers.

Enc=<symmetric encryption method>

Encryption method, with number of secret bits, such as AESGCM(128).

Mac=<message authentication code>

Message digest, such as SHA256.

Some examples for the output of SSL_CIPHER_description():

 ECDHE-RSA-AES256-GCM-SHA256 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AESGCM(256) Mac=AEAD
 RSA-PSK-AES256-CBC-SHA384 TLSv1.0 Kx=RSAPSK   Au=RSA  Enc=AES(256)  Mac=SHA384

HISTORY¶

SSL_CIPHER_description() was changed to return NULL on error, rather than a fixed string, in OpenSSL 1.1

SEE ALSO¶

COPYRIGHT¶

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>.