Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/Crypto/Cipher/__init__.py: 41%

1# 

2# A block cipher is instantiated as a combination of: 

3# 1. A base cipher (such as AES) 

4# 2. A mode of operation (such as CBC) 

5# 

6# Both items are implemented as C modules. 

7# 

8# The API of #1 is (replace "AES" with the name of the actual cipher): 

9# - AES_start_operaion(key) --> base_cipher_state 

10# - AES_encrypt(base_cipher_state, in, out, length) 

11# - AES_decrypt(base_cipher_state, in, out, length) 

12# - AES_stop_operation(base_cipher_state) 

13# 

14# Where base_cipher_state is AES_State, a struct with BlockBase (set of 

15# pointers to encrypt/decrypt/stop) followed by cipher-specific data. 

16# 

17# The API of #2 is (replace "CBC" with the name of the actual mode): 

18# - CBC_start_operation(base_cipher_state) --> mode_state 

19# - CBC_encrypt(mode_state, in, out, length) 

20# - CBC_decrypt(mode_state, in, out, length) 

21# - CBC_stop_operation(mode_state) 

22# 

23# where mode_state is a a pointer to base_cipher_state plus mode-specific data. 

24 

25from __future__ import annotations 

26 

27from typing import TYPE_CHECKING, TypedDict, Union 

28 

29if TYPE_CHECKING: 

30 from Crypto.Util.Counter import CounterParams 

31 

32Buffer = Union[bytes, bytearray, memoryview] 

33 

34 

35class BlockCipherParams(TypedDict, total=False): 

36 """Optional keyword arguments of ``new()`` for the classic block ciphers. 

37 Which ones are accepted depends on the mode of operation.""" 

38 

39 iv: Buffer 

40 IV: Buffer 

41 nonce: Buffer 

42 segment_size: int 

43 mac_len: int 

44 msg_len: int 

45 assoc_len: int 

46 initial_value: Union[int, Buffer] 

47 counter: CounterParams 

48 threads: int 

49 

50 

51def _create_cipher(factory, key, mode, *args, **kwargs): 

52 kwargs["key"] = key 

53 

54 if args: 

55 if mode in (8, 9, 10, 11, 12): 

56 if len(args) > 1: 

57 raise TypeError("Too many arguments for this mode") 

58 kwargs["nonce"] = args[0] 

59 elif mode in (2, 3, 5, 7): 

60 if len(args) > 1: 

61 raise TypeError("Too many arguments for this mode") 

62 kwargs["IV"] = args[0] 

63 elif mode == 6: 

64 if len(args) > 0: 

65 raise TypeError("Too many arguments for this mode") 

66 elif mode == 1: 

67 raise TypeError("IV is not meaningful for the ECB mode") 

68 

69 res = None 

70 extra_modes = kwargs.pop("add_aes_modes", False) 

71 

72 if mode == 1: 

73 from Crypto.Cipher._mode_ecb import _create_ecb_cipher 

74 

75 res = _create_ecb_cipher(factory, **kwargs) 

76 elif mode == 2: 

77 from Crypto.Cipher._mode_cbc import _create_cbc_cipher 

78 

79 res = _create_cbc_cipher(factory, **kwargs) 

80 elif mode == 3: 

81 from Crypto.Cipher._mode_cfb import _create_cfb_cipher 

82 

83 res = _create_cfb_cipher(factory, **kwargs) 

84 elif mode == 5: 

85 from Crypto.Cipher._mode_ofb import _create_ofb_cipher 

86 

87 res = _create_ofb_cipher(factory, **kwargs) 

88 elif mode == 6: 

89 from Crypto.Cipher._mode_ctr import _create_ctr_cipher 

90 

91 res = _create_ctr_cipher(factory, **kwargs) 

92 elif mode == 7: 

93 from Crypto.Cipher._mode_openpgp import _create_openpgp_cipher 

94 

95 res = _create_openpgp_cipher(factory, **kwargs) 

96 elif mode == 9: 

97 from Crypto.Cipher._mode_eax import _create_eax_cipher 

98 

99 res = _create_eax_cipher(factory, **kwargs) 

100 elif extra_modes: 

101 if mode == 8: 

102 from Crypto.Cipher._mode_ccm import _create_ccm_cipher 

103 

104 res = _create_ccm_cipher(factory, **kwargs) 

105 elif mode == 10: 

106 from Crypto.Cipher._mode_siv import _create_siv_cipher 

107 

108 res = _create_siv_cipher(factory, **kwargs) 

109 elif mode == 11: 

110 from Crypto.Cipher._mode_gcm import _create_gcm_cipher 

111 

112 res = _create_gcm_cipher(factory, **kwargs) 

113 elif mode == 12: 

114 from Crypto.Cipher._mode_ocb import _create_ocb_cipher 

115 

116 res = _create_ocb_cipher(factory, **kwargs) 

117 elif mode == 13: 

118 from Crypto.Cipher._mode_kw import _create_kw_cipher 

119 

120 res = _create_kw_cipher(factory, **kwargs) 

121 elif mode == 14: 

122 from Crypto.Cipher._mode_kwp import _create_kwp_cipher 

123 

124 res = _create_kwp_cipher(factory, **kwargs) 

125 

126 if res is None: 

127 raise ValueError("Mode not supported") 

128 

129 return res