=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);

=head1 DESCRIPTION

SSL_CIPHER_get_name() returns a pointer to the name of B<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 B<cipher>. If
B<alg_bits> is not NULL, it contains the number of bits processed by the
chosen algorithm. 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.
This is currently B<TLSv1/SSLv3>.
In some cases it should possibly return "TLSv1.2" but does not;
use SSL_CIPHER_description() instead.
If B<cipher> is NULL, "(NONE)" is returned.

SSL_CIPHER_description() returns a textual description of the cipher used
into the buffer B<buf> of length B<len> provided. B<len> must be at least
128 bytes, otherwise a pointer to the string "Buffer too small" is
returned. If B<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.

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.

=head1 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 B<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:

=over 4

=item <ciphername>

Textual representation of the cipher name.

=item <protocol version>

Protocol version: B<SSLv3>, B<TLSv1.2>. The TLSv1.0 ciphers are
flagged with SSLv3. No new ciphers were added by TLSv1.1.

=item Kx=<key exchange>

Key exchange method: B<RSA> (for export ciphers as B<RSA(512)> or
B<RSA(1024)>), B<DH> (for export ciphers as B<DH(512)> or B<DH(1024)>),
B<DH/RSA>, B<DH/DSS>, B<Fortezza>.

=item Au=<authentication>

Authentication method: B<RSA>, B<DSS>, B<DH>, B<None>. None is the
representation of anonymous ciphers.

=item Enc=<symmetric encryption method>

Encryption method with number of secret bits: B<DES(40)>, B<DES(56)>,
B<3DES(168)>, B<RC4(40)>, B<RC4(56)>, B<RC4(64)>, B<RC4(128)>,
B<RC2(40)>, B<RC2(56)>, B<RC2(128)>, B<IDEA(128)>, B<Fortezza>, B<None>.

=item Mac=<message authentication code>

Message digest: B<MD5>, B<SHA1>.

=item <export flag>

If the cipher is flagged exportable with respect to old US crypto
regulations, the word "B<export>" is printed.

=back

=head1 EXAMPLES

Some examples for the output of SSL_CIPHER_description():

 DHE-RSA-DES-CBC3-SHA    SSLv3 Kx=DH       Au=RSA  Enc=3DES(168) Mac=SHA1
 DHE-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

=head1 BUGS

If SSL_CIPHER_description() is called with B<cipher> being NULL, the
library crashes.

If SSL_CIPHER_description() cannot handle a built-in cipher, the according
description of the cipher property is B<unknown>. This case should not
occur.

=head1 RETURN VALUES

See DESCRIPTION

=head1 SEE ALSO

L<ssl(3)>, L<SSL_get_current_cipher(3)>,
L<SSL_get_ciphers(3)>, L<ciphers(1)>

=cut