SSL_CIPHER_get_name, SSL_CIPHER_get_bits, SSL_CIPHER_get_version, SSL_CIPHER_description — get SSL_CIPHER properties
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);
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.
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:
- 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.
- 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.
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
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.