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 a 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 the function does not; use SSL_CIPHER_description(3) 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. If buf is NULL, a buffer is allocated using asprintf(3); that buffer should be freed using the free(3) function. If len is too small, or if buf is NULL and the allocation fails, a pointer to the string “Buffer too small” is returned.

NOTES

The number of bits processed can be different from the secret bits. For example, an export cipher like EXP-RC4-MD5 has only 40 secret bits. The algorithm does use the full 128 bits (which would be returned for alg_bits), but 88 bits 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.

RETURN VALUES

See DESCRIPTION

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 complete list can be retrieved by invoking the following command:

$ openssl ciphers -v ALL

SEE ALSO

openssl(1), ssl(3), SSL_get_ciphers(3), SSL_get_current_cipher(3)

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.