codekingpro/portable-devtools

1# This file is dual licensed under the terms of the Apache License, Version2# 2.0, and the BSD License. See the LICENSE file in the root of this repository3# for complete details.4 5from __future__ import annotations6 7import abc8 9from cryptography.hazmat.primitives import hashes10from cryptography.hazmat.primitives._asymmetric import (11    AsymmetricPadding as AsymmetricPadding,12)13from cryptography.hazmat.primitives.asymmetric import rsa14 15 16class PKCS1v15(AsymmetricPadding):17    name = "EMSA-PKCS1-v1_5"18 19 20class _MaxLength:21    "Sentinel value for `MAX_LENGTH`."22 23 24class _Auto:25    "Sentinel value for `AUTO`."26 27 28class _DigestLength:29    "Sentinel value for `DIGEST_LENGTH`."30 31 32class PSS(AsymmetricPadding):33    MAX_LENGTH = _MaxLength()34    AUTO = _Auto()35    DIGEST_LENGTH = _DigestLength()36    name = "EMSA-PSS"37    _salt_length: int | _MaxLength | _Auto | _DigestLength38 39    def __init__(40        self,41        mgf: MGF,42        salt_length: int | _MaxLength | _Auto | _DigestLength,43    ) -> None:44        self._mgf = mgf45 46        if not isinstance(47            salt_length, (int, _MaxLength, _Auto, _DigestLength)48        ):49            raise TypeError(50                "salt_length must be an integer, MAX_LENGTH, "51                "DIGEST_LENGTH, or AUTO"52            )53 54        if isinstance(salt_length, int) and salt_length < 0:55            raise ValueError("salt_length must be zero or greater.")56 57        self._salt_length = salt_length58 59    @property60    def mgf(self) -> MGF:61        return self._mgf62 63 64class OAEP(AsymmetricPadding):65    name = "EME-OAEP"66 67    def __init__(68        self,69        mgf: MGF,70        algorithm: hashes.HashAlgorithm,71        label: bytes | None,72    ):73        if not isinstance(algorithm, hashes.HashAlgorithm):74            raise TypeError("Expected instance of hashes.HashAlgorithm.")75 76        self._mgf = mgf77        self._algorithm = algorithm78        self._label = label79 80    @property81    def algorithm(self) -> hashes.HashAlgorithm:82        return self._algorithm83 84    @property85    def mgf(self) -> MGF:86        return self._mgf87 88 89class MGF(metaclass=abc.ABCMeta):90    _algorithm: hashes.HashAlgorithm91 92 93class MGF1(MGF):94    def __init__(self, algorithm: hashes.HashAlgorithm):95        if not isinstance(algorithm, hashes.HashAlgorithm):96            raise TypeError("Expected instance of hashes.HashAlgorithm.")97 98        self._algorithm = algorithm99 100 101def calculate_max_pss_salt_length(102    key: rsa.RSAPrivateKey | rsa.RSAPublicKey,103    hash_algorithm: hashes.HashAlgorithm,104) -> int:105    if not isinstance(key, (rsa.RSAPrivateKey, rsa.RSAPublicKey)):106        raise TypeError("key must be an RSA public or private key")107    # bit length - 1 per RFC 3447108    emlen = (key.key_size + 6) // 8109    salt_length = emlen - hash_algorithm.digest_size - 2110    assert salt_length >= 0111    return salt_length112