Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/pypdf/_crypt_providers/_cryptography.py: 3%

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27 

28import secrets 

29 

30from cryptography import __version__ 

31from cryptography.hazmat.primitives import padding 

32from cryptography.hazmat.primitives.ciphers.algorithms import AES 

33 

34try: 

35 # 43.0.0 - https://cryptography.io/en/latest/changelog/#v43-0-0 

36 from cryptography.hazmat.decrepit.ciphers.algorithms import ARC4 

37except ImportError: 

38 from cryptography.hazmat.primitives.ciphers.algorithms import ARC4 

39from cryptography.hazmat.primitives.ciphers.base import Cipher 

40from cryptography.hazmat.primitives.ciphers.modes import CBC, ECB 

41 

42from pypdf._crypt_providers._base import CryptBase 

43 

44crypt_provider = ("cryptography", __version__) 

45 

46 

47class CryptRC4(CryptBase): 

48 def __init__(self, key: bytes) -> None: 

49 self.cipher = Cipher(ARC4(key), mode=None) 

50 

51 def encrypt(self, data: bytes) -> bytes: 

52 encryptor = self.cipher.encryptor() 

53 return encryptor.update(data) + encryptor.finalize() 

54 

55 def decrypt(self, data: bytes) -> bytes: 

56 decryptor = self.cipher.decryptor() 

57 return decryptor.update(data) + decryptor.finalize() 

58 

59 

60class CryptAES(CryptBase): 

61 def __init__(self, key: bytes) -> None: 

62 self.alg = AES(key) 

63 

64 def encrypt(self, data: bytes) -> bytes: 

65 iv = secrets.token_bytes(16) 

66 pad = padding.PKCS7(128).padder() 

67 data = pad.update(data) + pad.finalize() 

68 

69 cipher = Cipher(self.alg, CBC(iv)) 

70 encryptor = cipher.encryptor() 

71 return iv + encryptor.update(data) + encryptor.finalize() 

72 

73 def decrypt(self, data: bytes) -> bytes: 

74 iv = data[:16] 

75 data = data[16:] 

76 # for empty encrypted data 

77 if not data: 

78 return data 

79 

80 # just for robustness, it does not happen under normal circumstances 

81 if len(data) % 16 != 0: 

82 pad = padding.PKCS7(128).padder() 

83 data = pad.update(data) + pad.finalize() 

84 

85 cipher = Cipher(self.alg, CBC(iv)) 

86 decryptor = cipher.decryptor() 

87 d = decryptor.update(data) + decryptor.finalize() 

88 return d[: -d[-1]] 

89 

90 

91def rc4_encrypt(key: bytes, data: bytes) -> bytes: 

92 encryptor = Cipher(ARC4(key), mode=None).encryptor() 

93 return encryptor.update(data) + encryptor.finalize() 

94 

95 

96def rc4_decrypt(key: bytes, data: bytes) -> bytes: 

97 decryptor = Cipher(ARC4(key), mode=None).decryptor() 

98 return decryptor.update(data) + decryptor.finalize() 

99 

100 

101def aes_ecb_encrypt(key: bytes, data: bytes) -> bytes: 

102 encryptor = Cipher(AES(key), mode=ECB()).encryptor() 

103 return encryptor.update(data) + encryptor.finalize() 

104 

105 

106def aes_ecb_decrypt(key: bytes, data: bytes) -> bytes: 

107 decryptor = Cipher(AES(key), mode=ECB()).decryptor() 

108 return decryptor.update(data) + decryptor.finalize() 

109 

110 

111def aes_cbc_encrypt(key: bytes, iv: bytes, data: bytes) -> bytes: 

112 encryptor = Cipher(AES(key), mode=CBC(iv)).encryptor() 

113 return encryptor.update(data) + encryptor.finalize() 

114 

115 

116def aes_cbc_decrypt(key: bytes, iv: bytes, data: bytes) -> bytes: 

117 decryptor = Cipher(AES(key), mode=CBC(iv)).decryptor() 

118 return decryptor.update(data) + decryptor.finalize()