63 lines
1.9 KiB
Python
63 lines
1.9 KiB
Python
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# 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 typing
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from cryptography import utils
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from cryptography.exceptions import (
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AlreadyFinalized,
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InvalidKey,
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UnsupportedAlgorithm,
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_Reasons,
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)
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from cryptography.hazmat.bindings._rust import openssl as rust_openssl
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from cryptography.hazmat.primitives import constant_time, hashes
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from cryptography.hazmat.primitives.kdf import KeyDerivationFunction
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class PBKDF2HMAC(KeyDerivationFunction):
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def __init__(
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self,
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algorithm: hashes.HashAlgorithm,
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length: int,
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salt: bytes,
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iterations: int,
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backend: typing.Any = None,
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):
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from cryptography.hazmat.backends.openssl.backend import (
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backend as ossl,
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)
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if not ossl.pbkdf2_hmac_supported(algorithm):
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raise UnsupportedAlgorithm(
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f"{algorithm.name} is not supported for PBKDF2.",
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_Reasons.UNSUPPORTED_HASH,
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)
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self._used = False
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self._algorithm = algorithm
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self._length = length
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utils._check_bytes("salt", salt)
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self._salt = salt
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self._iterations = iterations
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def derive(self, key_material: bytes) -> bytes:
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if self._used:
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raise AlreadyFinalized("PBKDF2 instances can only be used once.")
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self._used = True
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return rust_openssl.kdf.derive_pbkdf2_hmac(
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key_material,
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self._algorithm,
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self._salt,
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self._iterations,
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self._length,
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)
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def verify(self, key_material: bytes, expected_key: bytes) -> None:
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derived_key = self.derive(key_material)
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if not constant_time.bytes_eq(derived_key, expected_key):
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raise InvalidKey("Keys do not match.")
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