SSL_CTX_set_cipher_list(3)					      OpenSSL						SSL_CTX_set_cipher_list(3)

NAME

       SSL_CTX_set_cipher_list, SSL_set_cipher_list - choose list of available SSL_CIPHERs

LIBRARY

       libcrypto, -lcrypto

SYNOPSIS

	#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

       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
       openssl_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

       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.

       If the cipher list does not contain any SSLv2 cipher suites (this is the default) then SSLv2 is effectively disabled and neither clients
       nor servers will attempt to use SSLv2.

RETURN VALUES

       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

       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), openssl_ciphers(1)

1.0.1i								    2014-08-10						SSL_CTX_set_cipher_list(3)