openssl/doc/ssl/SSL_CIPHER_get_name.pod
Todd Short 3ec13237f0 Add cipher query functions
Add functions to determine authentication, key-exchange, FIPS and AEAD.

Reviewed-by: Emilia Käsper <emilia@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
2016-03-08 09:19:15 -05:00

115 lines
3.5 KiB
Text

=pod
=head1 NAME
SSL_CIPHER_get_name, SSL_CIPHER_get_bits, SSL_CIPHER_get_version, SSL_CIPHER_description - get SSL_CIPHER properties
=head1 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);
=head1 DESCRIPTION
SSL_CIPHER_get_name() returns a pointer to the name of B<cipher>. If the
B<cipher> is NULL, it returns "(NONE)".
SSL_CIPHER_get_bits() returns the number of secret bits used for B<cipher>.
If B<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 B<cipher> is NULL.
SSL_CIPHER_get_cipher_nid() returns the cipher NID corresponding to B<c>.
If there is no cipher (e.g. for ciphersuites with no encryption) then
B<NID_undef> is returned.
SSL_CIPHER_get_digest_nid() returns the digest NID corresponding to the MAC
used by B<c>. If there is no digest (e.g. for AEAD ciphersuites) then
B<NID_undef> is returned.
SSL_CIPHER_get_kx_nid() returns the key exchange NID corresponding to the method
used by B<c>. If there is no key exchange, then B<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 B<c>. If there is no authentication, then B<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 B<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 B<buf> of length B<len> provided. If B<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,
B<NULL> is returned.
The string returned by SSL_CIPHER_description() consists of several fields
separated by whitespace:
=over 4
=item <ciphername>
Textual representation of the cipher name.
=item <protocol version>
Protocol version, such as B<TLSv1.2>, when the cipher was first defined.
=item Kx=<key exchange>
Key exchange method such as B<RSA>, B<ECDHE>, etc.
=item Au=<authentication>
Authentication method such as B<RSA>, B<None>, etc.. None is the
representation of anonymous ciphers.
=item Enc=<symmetric encryption method>
Encryption method, with number of secret bits, such as B<AESGCM(128)>.
=item Mac=<message authentication code>
Message digest, such as B<SHA256>.
=back
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
=head1 HISTORY
SSL_CIPHER_get_version() was updated to always return the correct protocol
string in OpenSSL 1.1.
SSL_CIPHER_description() was changed to return B<NULL> on error,
rather than a fixed string, in OpenSSL 1.1
=head1 SEE ALSO
L<ssl(3)>, L<SSL_get_current_cipher(3)>,
L<SSL_get_ciphers(3)>, L<ciphers(1)>
=cut