Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/cryptography/hazmat/primitives/hmac.py: 80%

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 AlreadyFinalized 

10from cryptography.hazmat.backends.openssl.hmac import _HMACContext 

11from cryptography.hazmat.primitives import hashes 

12 

13 

14class HMAC(hashes.HashContext): 

15 _ctx: typing.Optional[_HMACContext] 

16 

17 def __init__( 

18 self, 

19 key: bytes, 

20 algorithm: hashes.HashAlgorithm, 

21 backend: typing.Any = None, 

22 ctx=None, 

23 ): 

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

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

26 self._algorithm = algorithm 

27 

28 self._key = key 

29 if ctx is None: 

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

31 backend as ossl, 

32 ) 

33 

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

35 else: 

36 self._ctx = ctx 

37 

38 @property 

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

40 return self._algorithm 

41 

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

43 if self._ctx is None: 

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

45 utils._check_byteslike("data", data) 

46 self._ctx.update(data) 

47 

48 def copy(self) -> "HMAC": 

49 if self._ctx is None: 

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

51 return HMAC( 

52 self._key, 

53 self.algorithm, 

54 ctx=self._ctx.copy(), 

55 ) 

56 

57 def finalize(self) -> bytes: 

58 if self._ctx is None: 

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

60 digest = self._ctx.finalize() 

61 self._ctx = None 

62 return digest 

63 

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

65 utils._check_bytes("signature", signature) 

66 if self._ctx is None: 

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

68 

69 ctx, self._ctx = self._ctx, None 

70 ctx.verify(signature)