pushbullet.py 文件源码

def _decrypt_data(self, data):
        assert self._encryption_key

        from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
        from cryptography.hazmat.backends import default_backend
        from binascii import a2b_base64

        key = self._encryption_key
        encoded_message = a2b_base64(data)

        version = encoded_message[0:1]
        tag = encoded_message[1:17]
        initialization_vector = encoded_message[17:29]
        encrypted_message = encoded_message[29:]

        if version != b"1":
            raise Exception("Invalid Version")

        cipher = Cipher(algorithms.AES(key),
                        modes.GCM(initialization_vector, tag),
                        backend=default_backend())
        decryptor = cipher.decryptor()

        decrypted = decryptor.update(encrypted_message) + decryptor.finalize()
        decrypted = decrypted.decode()

        return(decrypted)