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SSL_CIPHER_GET_NAME(3ossl) OpenSSL SSL_CIPHER_GET_NAME(3ossl)
NAME
SSL_CIPHER_get_name, SSL_CIPHER_standard_name, OPENSSL_cipher_name,
SSL_CIPHER_get_bits, SSL_CIPHER_get_version, SSL_CIPHER_description,
SSL_CIPHER_get_cipher_nid, SSL_CIPHER_get_digest_nid,
SSL_CIPHER_get_handshake_digest, SSL_CIPHER_get_kx_nid,
SSL_CIPHER_get_auth_nid, SSL_CIPHER_is_aead, SSL_CIPHER_find,
SSL_CIPHER_get_id, SSL_CIPHER_get_protocol_id - get SSL_CIPHER
properties
SYNOPSIS
#include <openssl/ssl.h>
const char *SSL_CIPHER_get_name(const SSL_CIPHER *cipher);
const char *SSL_CIPHER_standard_name(const SSL_CIPHER *cipher);
const char *OPENSSL_cipher_name(const char *stdname);
int SSL_CIPHER_get_bits(const SSL_CIPHER *cipher, int *alg_bits);
const 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);
const EVP_MD *SSL_CIPHER_get_handshake_digest(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);
const SSL_CIPHER *SSL_CIPHER_find(SSL *ssl, const unsigned char *ptr);
uint32_t SSL_CIPHER_get_id(const SSL_CIPHER *c);
uint32_t SSL_CIPHER_get_protocol_id(const SSL_CIPHER *c);
DESCRIPTION
SSL_CIPHER_get_name() returns a pointer to the name of cipher. If the
cipher is NULL, it returns "(NONE)".
SSL_CIPHER_standard_name() returns a pointer to the standard RFC name
of cipher. If the cipher is NULL, it returns "(NONE)". If the cipher
has no standard name, it returns NULL. If cipher was defined in both
SSLv3 and TLS, it returns the TLS name.
OPENSSL_cipher_name() returns a pointer to the OpenSSL name of stdname.
If the stdname is NULL, or stdname has no corresponding OpenSSL name,
it returns "(NONE)". Where both exist, stdname should be the TLS name
rather than the SSLv3 name.
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 cipher suites with no encryption) then
NID_undef is returned.
SSL_CIPHER_get_digest_nid() returns the digest NID corresponding to the
MAC used by c during record encryption/decryption. If there is no
digest (e.g. for AEAD cipher suites) then NID_undef is returned.
the method used by c. If there is no key exchange, then NID_undef is
returned. If any appropriate key exchange algorithm can be used (as in
the case of TLS 1.3 cipher suites) NID_kx_any 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. If any appropriate authentication algorithm can be used
(as in the case of TLS 1.3 cipher suites) NID_auth_any 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_find() returns a SSL_CIPHER structure which has the cipher
ID stored in ptr. The ptr parameter is a two element array of char,
which stores the two-byte TLS cipher ID (as allocated by IANA) in
network byte order. This parameter is usually retrieved from a TLS
packet by using functions like SSL_client_hello_get0_ciphers(3).
SSL_CIPHER_find() returns NULL if an error occurs or the indicated
cipher is not found.
SSL_CIPHER_get_id() returns the OpenSSL-specific ID of the given cipher
c. That ID is not the same as the IANA-specific ID.
SSL_CIPHER_get_protocol_id() returns the two-byte ID used in the TLS
protocol of the given cipher c.
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>
The minimum protocol version that the ciphersuite supports, such as
TLSv1.2. Note that this is not always the same as the protocol
version in which the ciphersuite was first defined because some
ciphersuites are backwards compatible with earlier protocol
versions.
Kx=<key exchange>
Key exchange method such as RSA, ECDHE, etc.
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
RETURN VALUES
SSL_CIPHER_get_name(), SSL_CIPHER_standard_name(),
OPENSSL_cipher_name(), SSL_CIPHER_get_version() and
SSL_CIPHER_description() return the corresponding value in a NUL-
terminated string for a specific cipher or "(NONE)" if the cipher is
not found.
SSL_CIPHER_get_bits() returns a positive integer representing the
number of secret bits or 0 if an error occurred.
SSL_CIPHER_get_cipher_nid(), SSL_CIPHER_get_digest_nid(),
SSL_CIPHER_get_kx_nid() and SSL_CIPHER_get_auth_nid() return the NID
value or NID_undef if an error occurred.
SSL_CIPHER_get_handshake_digest() returns a valid EVP_MD structure or
NULL if an error occurred.
SSL_CIPHER_is_aead() returns 1 if the cipher is AEAD or 0 otherwise.
SSL_CIPHER_find() returns a valid SSL_CIPHER structure or NULL if an
error occurred.
SSL_CIPHER_get_id() returns a 4-byte integer representing the OpenSSL-
specific ID.
SSL_CIPHER_get_protocol_id() returns a 2-byte integer representing the
TLS protocol-specific ID.
SEE ALSO
ssl(7), SSL_get_current_cipher(3), SSL_get_ciphers(3),
openssl-ciphers(1)
HISTORY
The SSL_CIPHER_get_version() function was updated to always return the
correct protocol string in OpenSSL 1.1.0.
The SSL_CIPHER_description() function was changed to return NULL on
error, rather than a fixed string, in OpenSSL 1.1.0.
The SSL_CIPHER_get_handshake_digest() function was added in OpenSSL
1.1.1.
The SSL_CIPHER_standard_name() function was globally available in
OpenSSL 1.1.1.
Before OpenSSL 1.1.1, tracing (enable-ssl-trace argument to Configure)
was required to enable this function.
The OPENSSL_cipher_name() function was added in OpenSSL 1.1.1.
COPYRIGHT
Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.