NAME¶
SSL_CIPHER_get_name, SSL_CIPHER_get_bits, SSL_CIPHER_get_version,
SSL_CIPHER_description - get SSL_CIPHER properties
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);
DESCRIPTION¶
SSL_CIPHER_get_name() returns a pointer to the name of
cipher. If
the argument is the NULL pointer, a pointer to the constant value
"NONE" is returned.
SSL_CIPHER_get_bits() returns the number of secret bits used for
cipher. If
alg_bits is not NULL, it contains the number of bits
processed by the chosen algorithm. 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. This is currently
SSLv2
or
TLSv1/SSLv3. In some cases it should possibly return
"TLSv1.2" but does not; use
SSL_CIPHER_description() instead.
If
cipher is NULL, "(NONE)" is returned.
SSL_CIPHER_description() returns a textual description of the cipher used
into the buffer
buf of length
len provided.
len must be
at least 128 bytes, otherwise a pointer to the string "Buffer too
small" is returned. If
buf is NULL, a buffer of 128 bytes is
allocated using
OPENSSL_malloc(). If the allocation fails, a pointer to
the string "OPENSSL_malloc Error" is returned.
NOTES¶
The number of bits processed can be different from the secret bits. An export
cipher like e.g. EXP-RC4-MD5 has only 40 secret bits. The algorithm does use
the full 128 bits (which would be returned for
alg_bits), of which
however 88bits are fixed. The search space is hence only 40 bits.
The string returned by
SSL_CIPHER_description() in case of success
consists of cleartext information separated by one or more blanks in the
following sequence:
- <ciphername>
- Textual representation of the cipher name.
- <protocol version>
- Protocol version: SSLv2, SSLv3, TLSv1.2. The TLSv1.0
ciphers are flagged with SSLv3. No new ciphers were added by TLSv1.1.
- Kx=<key exchange>
- Key exchange method: RSA (for export ciphers as RSA(512) or
RSA(1024)), DH (for export ciphers as DH(512) or
DH(1024)), DH/RSA, DH/DSS, Fortezza.
- Au=<authentication>
- Authentication method: RSA, DSS, DH, None.
None is the representation of anonymous ciphers.
- Enc=<symmetric encryption method>
- Encryption method with number of secret bits: DES(40),
DES(56), 3DES(168), RC4(40), RC4(56),
RC4(64), RC4(128), RC2(40), RC2(56),
RC2(128), IDEA(128), Fortezza, None.
- Mac=<message authentication code>
- Message digest: MD5, SHA1.
- <export flag>
- If the cipher is flagged exportable with respect to old US crypto
regulations, the word " export" is printed.
EXAMPLES¶
Some examples for the output of
SSL_CIPHER_description():
EDH-RSA-DES-CBC3-SHA SSLv3 Kx=DH Au=RSA Enc=3DES(168) Mac=SHA1
EDH-DSS-DES-CBC3-SHA SSLv3 Kx=DH Au=DSS Enc=3DES(168) Mac=SHA1
RC4-MD5 SSLv3 Kx=RSA Au=RSA Enc=RC4(128) Mac=MD5
EXP-RC4-MD5 SSLv3 Kx=RSA(512) Au=RSA Enc=RC4(40) Mac=MD5 export
A comp[lete list can be retrieved by invoking the following command:
openssl ciphers -v ALL
BUGS¶
If
SSL_CIPHER_description() is called with
cipher being NULL, the
library crashes.
If
SSL_CIPHER_description() cannot handle a built-in cipher, the
according description of the cipher property is
unknown. This case
should not occur.
The standard terminology for ephemeral Diffie-Hellman schemes is DHE (finite
field) or ECDHE (elliptic curve). This version of OpenSSL idiosyncratically
reports these schemes as EDH and EECDH, even though it also accepts the
standard terminology.
It is recommended to use the standard terminology (DHE and ECDHE) during
configuration (e.g. via SSL_CTX_set_cipher_list) for clarity of configuration.
OpenSSL versions after 1.0.2 will report the standard terms via
SSL_CIPHER_get_name and SSL_CIPHER_description.
RETURN VALUES¶
See DESCRIPTION
SEE ALSO¶
ssl(3),
SSL_get_current_cipher(3),
SSL_get_ciphers(3),
ciphers(1),
SSL_CTX_set_cipher_list(3)