# This file is dual licensed under the terms of the Apache License, Version # 2.0, and the BSD License. See the LICENSE file in the root of this repository # for complete details. from __future__ import annotations import abc import typing # This exists to break an import cycle. It is normally accessible from the # ciphers module. class CipherAlgorithm(metaclass=abc.ABCMeta): @property @abc.abstractmethod def name(self) -> str: """ A string naming this mode (e.g. "AES", "Camellia"). """ @property @abc.abstractmethod def key_sizes(self) -> typing.FrozenSet[int]: """ Valid key sizes for this algorithm in bits """ @property @abc.abstractmethod def key_size(self) -> int: """ The size of the key being used as an integer in bits (e.g. 128, 256). """ class BlockCipherAlgorithm(CipherAlgorithm): key: bytes @property @abc.abstractmethod def block_size(self) -> int: """ The size of a block as an integer in bits (e.g. 64, 128). """