@classmethod
def register(cls, name, public_key_type, create_verifier):
    """Register a signature key type.

        :param name: the name of the signature key type
        :param public_key_type: e.g. RSAPublicKey, DSAPublicKey, etc.
        :param create_verifier: a function to create a verifier for this type
        """
    cls.REGISTERED_TYPES[name] = cls(name, public_key_type, create_verifier)
