Updated explanation.

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, the respective is valid for DSA ciphers. Ciphers using EDH need

a certificate and key and DH-parameters.

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. RSA ciphers using EDH need a certificate and key and

additional DH-parameters.

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.

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.

=head1 RETURN VALUES