Decrypt the serialized, encrypted string.

    Args:
       encrypted_response: A serialized and encrypted string.

    Returns:
       a Packed_Message_List rdfvalue

def DecryptMessage(self, encrypted_response):
    """Decrypt the serialized, encrypted string.

    Args:
       encrypted_response: A serialized and encrypted string.

    Returns:
       a Packed_Message_List rdfvalue
    """
    try:
      response_comms = rdf_flows.ClientCommunication.FromSerializedString(
          encrypted_response)
      return self.DecodeMessages(response_comms)
    except (rdfvalue.DecodeError, type_info.TypeValueError, ValueError,
            AttributeError) as e:
      raise DecodingError("Error while decrypting messages: %s" % e)