extract_secret (OpenID::Consumer::DiffieHellmanSession)

    # File lib/openid/consumer/associationmanager.rb, line 39
          def extract_secret(response)
            dh_server_public64 = response.get_arg(OPENID_NS, 'dh_server_public',
                                                  NO_DEFAULT)
            enc_mac_key64 = response.get_arg(OPENID_NS, 'enc_mac_key', NO_DEFAULT)
            dh_server_public = CryptUtil.base64_to_num(dh_server_public64)
            enc_mac_key = Util.from_base64(enc_mac_key64)
            return @dh.xor_secret(self.class.hashfunc,
                                  dh_server_public, enc_mac_key)
          end