Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/cryptography/hazmat/primitives/asymmetric/padding.py: 58%

1# This file is dual licensed under the terms of the Apache License, Version 

2# 2.0, and the BSD License. See the LICENSE file in the root of this repository 

3# for complete details. 

4 

5from __future__ import annotations 

6 

7import abc 

8 

9from cryptography.hazmat.primitives import hashes 

10from cryptography.hazmat.primitives._asymmetric import ( 

11 AsymmetricPadding as AsymmetricPadding, 

12) 

13from cryptography.hazmat.primitives.asymmetric import rsa 

14 

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 | _DigestLength 

38 

39 def __init__( 

40 self, 

41 mgf: MGF, 

42 salt_length: int | _MaxLength | _Auto | _DigestLength, 

43 ) -> None: 

44 self._mgf = mgf 

45 

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_length 

58 

59 @property 

60 def mgf(self) -> MGF: 

61 return self._mgf 

62 

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 = mgf 

77 self._algorithm = algorithm 

78 self._label = label 

79 

80 @property 

81 def algorithm(self) -> hashes.HashAlgorithm: 

82 return self._algorithm 

83 

84 @property 

85 def mgf(self) -> MGF: 

86 return self._mgf 

87 

88 

89class MGF(metaclass=abc.ABCMeta): 

90 _algorithm: hashes.HashAlgorithm 

91 

92 

93class MGF1(MGF): 

94 MAX_LENGTH = _MaxLength() 

95 

96 def __init__(self, algorithm: hashes.HashAlgorithm): 

97 if not isinstance(algorithm, hashes.HashAlgorithm): 

98 raise TypeError("Expected instance of hashes.HashAlgorithm.") 

99 

100 self._algorithm = algorithm 

101 

102 

103def calculate_max_pss_salt_length( 

104 key: rsa.RSAPrivateKey | rsa.RSAPublicKey, 

105 hash_algorithm: hashes.HashAlgorithm, 

106) -> int: 

107 if not isinstance(key, (rsa.RSAPrivateKey, rsa.RSAPublicKey)): 

108 raise TypeError("key must be an RSA public or private key") 

109 # bit length - 1 per RFC 3447 

110 emlen = (key.key_size + 6) // 8 

111 salt_length = emlen - hash_algorithm.digest_size - 2 

112 assert salt_length >= 0 

113 return salt_length