mirror of http://git.sairate.top/sairate/doc.git
59 lines
1.5 KiB
Python
59 lines
1.5 KiB
Python
# This file is dual licensed under the terms of the Apache License, Version
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# 2.0, and the BSD License. See the LICENSE file in the root of this repository
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# for complete details.
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from __future__ import annotations
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import abc
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from cryptography import utils
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# This exists to break an import cycle. It is normally accessible from the
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# ciphers module.
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class CipherAlgorithm(metaclass=abc.ABCMeta):
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@property
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@abc.abstractmethod
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def name(self) -> str:
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"""
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A string naming this mode (e.g. "AES", "Camellia").
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"""
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@property
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@abc.abstractmethod
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def key_sizes(self) -> frozenset[int]:
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"""
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Valid key sizes for this algorithm in bits
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"""
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@property
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@abc.abstractmethod
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def key_size(self) -> int:
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"""
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The size of the key being used as an integer in bits (e.g. 128, 256).
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"""
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class BlockCipherAlgorithm(CipherAlgorithm):
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key: bytes
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@property
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@abc.abstractmethod
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def block_size(self) -> int:
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"""
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The size of a block as an integer in bits (e.g. 64, 128).
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"""
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def _verify_key_size(algorithm: CipherAlgorithm, key: bytes) -> bytes:
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# Verify that the key is instance of bytes
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utils._check_byteslike("key", key)
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# Verify that the key size matches the expected key size
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if len(key) * 8 not in algorithm.key_sizes:
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raise ValueError(
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f"Invalid key size ({len(key) * 8}) for {algorithm.name}."
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)
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return key
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