Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/cryptography/hazmat/primitives/asymmetric/padding.py: 57%

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 

5 

6import abc 

7import typing 

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: typing.Union[int, _MaxLength, _Auto, _DigestLength] 

38 

39 def __init__( 

40 self, 

41 mgf: "MGF", 

42 salt_length: typing.Union[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 

60class OAEP(AsymmetricPadding): 

61 name = "EME-OAEP" 

62 

63 def __init__( 

64 self, 

65 mgf: "MGF", 

66 algorithm: hashes.HashAlgorithm, 

67 label: typing.Optional[bytes], 

68 ): 

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

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

71 

72 self._mgf = mgf 

73 self._algorithm = algorithm 

74 self._label = label 

75 

76 

77class MGF(metaclass=abc.ABCMeta): 

78 _algorithm: hashes.HashAlgorithm 

79 

80 

81class MGF1(MGF): 

82 MAX_LENGTH = _MaxLength() 

83 

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

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

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

87 

88 self._algorithm = algorithm 

89 

90 

91def calculate_max_pss_salt_length( 

92 key: typing.Union["rsa.RSAPrivateKey", "rsa.RSAPublicKey"], 

93 hash_algorithm: hashes.HashAlgorithm, 

94) -> int: 

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

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

97 # bit length - 1 per RFC 3447 

98 emlen = (key.key_size + 6) // 8 

99 salt_length = emlen - hash_algorithm.digest_size - 2 

100 assert salt_length >= 0 

101 return salt_length