Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/cryptography/hazmat/primitives/hmac.py: 45%

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 typing 

7 

8from cryptography import utils 

9from cryptography.exceptions import ( 

10 AlreadyFinalized, 

11) 

12from cryptography.hazmat.backends.openssl.hmac import _HMACContext 

13from cryptography.hazmat.primitives import hashes 

14 

15 

16class HMAC(hashes.HashContext): 

17 _ctx: typing.Optional[_HMACContext] 

18 

19 def __init__( 

20 self, 

21 key: bytes, 

22 algorithm: hashes.HashAlgorithm, 

23 backend: typing.Any = None, 

24 ctx=None, 

25 ): 

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

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

28 self._algorithm = algorithm 

29 

30 self._key = key 

31 if ctx is None: 

32 from cryptography.hazmat.backends.openssl.backend import ( 

33 backend as ossl, 

34 ) 

35 

36 self._ctx = ossl.create_hmac_ctx(key, self.algorithm) 

37 else: 

38 self._ctx = ctx 

39 

40 @property 

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

42 return self._algorithm 

43 

44 def update(self, data: bytes) -> None: 

45 if self._ctx is None: 

46 raise AlreadyFinalized("Context was already finalized.") 

47 utils._check_byteslike("data", data) 

48 self._ctx.update(data) 

49 

50 def copy(self) -> "HMAC": 

51 if self._ctx is None: 

52 raise AlreadyFinalized("Context was already finalized.") 

53 return HMAC( 

54 self._key, 

55 self.algorithm, 

56 ctx=self._ctx.copy(), 

57 ) 

58 

59 def finalize(self) -> bytes: 

60 if self._ctx is None: 

61 raise AlreadyFinalized("Context was already finalized.") 

62 digest = self._ctx.finalize() 

63 self._ctx = None 

64 return digest 

65 

66 def verify(self, signature: bytes) -> None: 

67 utils._check_bytes("signature", signature) 

68 if self._ctx is None: 

69 raise AlreadyFinalized("Context was already finalized.") 

70 

71 ctx, self._ctx = self._ctx, None 

72 ctx.verify(signature)