@staticmethod
def _extractSignature(interest, wireFormat):
    """
        Extract the signature information from the interest name.

        :param Interest interest: The interest whose signature is needed.
        :param WireFormat wireFormat: The wire format used to decode signature
          information from the interest name.
        :return: The Signature object, or None if can't decode.
        :rtype: Signature
        """
    if interest.getName().size() < 2:
        return None
    try:
        return wireFormat.decodeSignatureInfoAndValue(interest.getName().
            get(-2).getValue().buf(), interest.getName().get(-1).getValue()
            .buf(), False)
    except:
        return None
