NAME    [Toc]    [Back]

       SSL_CTX_set_cipher_list, SSL_set_cipher_list - choose list
       of available SSL_CIPHERs

SYNOPSIS    [Toc]    [Back]

        #include <openssl/ssl.h>

        int   SSL_CTX_set_cipher_list(SSL_CTX  *ctx,  const  char
*str);
        int SSL_set_cipher_list(SSL *ssl, const char *str);

DESCRIPTION    [Toc]    [Back]

       SSL_CTX_set_cipher_list() sets the list of available
       ciphers for ctx using the control string str. The format
       of the string is described in ciphers(1). The list of
       ciphers is inherited by all ssl objects created from  ctx.

       SSL_set_cipher_list() sets the list of ciphers only for
       ssl.

NOTES    [Toc]    [Back]

       The control string str should be universally usable and
       not depend on details of the library configuration
       (ciphers compiled in). Thus no syntax checking takes
       place. Items that are not recognized, because the corresponding
 ciphers are not compiled in or because they are
       mistyped, are simply ignored. Failure is only flagged if
       no ciphers could be collected at all.

       It should be noted, that inclusion of a cipher to be used
       into the list is a necessary condition. On the client
       side, the inclusion into the list is also sufficient. On
       the server side, additional restrictions apply. All
       ciphers have additional requirements. ADH ciphers don't
       need  a certificate, but DH-parameters must have been set.
       All other ciphers need a corresponding certificate and
       key.

       A RSA cipher can only be chosen, when a RSA certificate is
       available.  RSA export ciphers with a keylength of 512
       bits for the RSA key require a temporary 512 bit RSA key,
       as typically the supplied key has a length of 1024 bit
       (see SSL_CTX_set_tmp_rsa_callback(3)).  RSA ciphers using
       EDH need a certificate and key and additional DH-parameters
 (see SSL_CTX_set_tmp_dh_callback(3)).

       A DSA cipher can only be chosen, when a DSA certificate is
       available.  DSA ciphers always use DH key exchange and
       therefore need DH-parameters (see
       SSL_CTX_set_tmp_dh_callback(3)).

       When these conditions are not met for any cipher in the
       list (e.g. a client only supports export RSA ciphers with
       a asymmetric key length of 512 bits and the server is not
       configured to use temporary RSA keys), the "no shared
       cipher" (SSL_R_NO_SHARED_CIPHER) error is generated and
       the handshake will fail.

RETURN VALUES    [Toc]    [Back]

       SSL_CTX_set_cipher_list() and SSL_set_cipher_list() return
       1 if any cipher could be selected and 0 on complete failure.

SEE ALSO    [Toc]    [Back]

       ssl(3), SSL_get_ciphers(3), SSL_CTX_use_certificate(3),
       SSL_CTX_set_tmp_rsa_callback(3),
       SSL_CTX_set_tmp_dh_callback(3), ciphers(1)


OpenBSD 3.6                 2002-05-14                          2