ssl_cipher_description(3) - Linux man page

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 the protocol version for cipher, currently "SSLv2", "SSLv3", or "TLSv1". 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. The TLSv1 ciphers are flagged with SSLv3.
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

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.

Return Values

See DESCRIPTION