Auth_OpenID_DiffieHellmanSHA1ServerSession::answer PHP Method

    function answer($secret)
    {
        $lib = Auth_OpenID_getMathLib();
        $mac_key = $this->dh->xorSecret($this->consumer_pubkey, $secret, $this->hash_func);
        return array('dh_server_public' => $lib->longToBase64($this->dh->public), 'enc_mac_key' => base64_encode($mac_key));
    }