# Copyright 2016 Google Inc. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Base classes for cryptographic signers and verifiers.""" import abc import six @six.add_metaclass(abc.ABCMeta) class Verifier(object): """Abstract base class for crytographic signature verifiers.""" @abc.abstractmethod def verify(self, message, signature): """Verifies a message against a cryptographic signature. Args: message (Union[str, bytes]): The message to verify. signature (Union[str, bytes]): The cryptography signature to check. Returns: bool: True if message was signed by the private key associated with the public key that this object was constructed with. """ # pylint: disable=missing-raises-doc,redundant-returns-doc # (pylint doesn't recognize that this is abstract) raise NotImplementedError('Verify must be implemented') @six.add_metaclass(abc.ABCMeta) class Signer(object): """Abstract base class for cryptographic signers.""" @abc.abstractproperty def key_id(self): """Optional[str]: The key ID used to identify this private key.""" raise NotImplementedError('Key id must be implemented') @abc.abstractmethod def sign(self, message): """Signs a message. Args: message (Union[str, bytes]): The message to be signed. Returns: bytes: The signature of the message. """ # pylint: disable=missing-raises-doc,redundant-returns-doc # (pylint doesn't recognize that this is abstract) raise NotImplementedError('Sign must be implemented')