Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/pypdf/_crypt_providers/_pycryptodome.py: 55%

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3# 

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9# this list of conditions and the following disclaimer. 

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11# this list of conditions and the following disclaimer in the documentation 

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14# derived from this software without specific prior written permission. 

15# 

16# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 

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25# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 

26# POSSIBILITY OF SUCH DAMAGE. 

27 

28import secrets 

29 

30from Crypto import __version__ 

31from Crypto.Cipher import AES, ARC4 

32from Crypto.Util.Padding import pad, unpad 

33 

34from pypdf._crypt_providers._base import CryptBase 

35from pypdf._utils import logger_warning 

36from pypdf.errors import PdfStreamError 

37 

38crypt_provider = ("pycryptodome", __version__) 

39 

40 

41class CryptRC4(CryptBase): 

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

43 self.key = key 

44 

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

46 return ARC4.ARC4Cipher(self.key).encrypt(data) 

47 

48 def decrypt(self, data: bytes, *, strict: bool = True) -> bytes: 

49 return ARC4.ARC4Cipher(self.key).decrypt(data) 

50 

51 

52class CryptAES(CryptBase): 

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

54 self.key = key 

55 

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

57 iv = secrets.token_bytes(16) 

58 padded_data = pad(data, 16) 

59 aes = AES.new(self.key, AES.MODE_CBC, iv) 

60 return iv + aes.encrypt(padded_data) 

61 

62 def decrypt(self, data: bytes, *, strict: bool = True) -> bytes: 

63 iv = data[:16] 

64 data = data[16:] 

65 # for empty encrypted data 

66 if not data: 

67 return data 

68 

69 if not strict and len(data) % 16 != 0: 

70 logger_warning("Adding missing padding.", src=__name__) 

71 data = pad(data, 16) 

72 

73 aes = AES.new(self.key, AES.MODE_CBC, iv) 

74 try: 

75 padded_data = aes.decrypt(data) 

76 except ValueError as exception: 

77 # Only raised in strict mode. Non-strict mode fixes padding. 

78 raise PdfStreamError(exception) 

79 

80 try: 

81 return unpad(padded_data, 16) 

82 except ValueError as exception: 

83 if strict: 

84 raise PdfStreamError(exception) 

85 logger_warning(f"Ignoring padding error: {exception}", src=__name__) 

86 return padded_data[: -padded_data[-1]] 

87 

88 

89def rc4_encrypt(key: bytes, data: bytes) -> bytes: 

90 return ARC4.ARC4Cipher(key).encrypt(data) 

91 

92 

93def rc4_decrypt(key: bytes, data: bytes) -> bytes: 

94 return ARC4.ARC4Cipher(key).decrypt(data) 

95 

96 

97def aes_ecb_encrypt(key: bytes, data: bytes) -> bytes: 

98 return AES.new(key, AES.MODE_ECB).encrypt(data) 

99 

100 

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

102 return AES.new(key, AES.MODE_ECB).decrypt(data) 

103 

104 

105def aes_cbc_encrypt(key: bytes, iv: bytes, data: bytes) -> bytes: 

106 return AES.new(key, AES.MODE_CBC, iv).encrypt(data) 

107 

108 

109def aes_cbc_decrypt(key: bytes, iv: bytes, data: bytes) -> bytes: 

110 return AES.new(key, AES.MODE_CBC, iv).decrypt(data)