Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/Crypto/Random/Fortuna/SHAd256.py: 79%

1# -*- coding: ascii -*- 

2# 

3# Random/Fortuna/SHAd256.py : SHA_d-256 hash function implementation 

4# 

5# Written in 2008 by Dwayne C. Litzenberger <dlitz@dlitz.net> 

6# 

7# =================================================================== 

8# The contents of this file are dedicated to the public domain. To 

9# the extent that dedication to the public domain is not available, 

10# everyone is granted a worldwide, perpetual, royalty-free, 

11# non-exclusive license to exercise all rights associated with the 

12# contents of this file for any purpose whatsoever. 

13# No rights are reserved. 

14# 

15# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 

16# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 

17# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 

18# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 

19# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 

20# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 

21# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 

22# SOFTWARE. 

23# =================================================================== 

24 

25"""\ 

26SHA_d-256 hash function implementation. 

27 

28This module should comply with PEP 247. 

29""" 

30 

31__revision__ = "$Id$" 

32__all__ = ['new', 'digest_size'] 

33 

34import sys 

35if sys.version_info[0] == 2 and sys.version_info[1] == 1: 

36 from Crypto.Util.py21compat import * 

37from Crypto.Util.py3compat import * 

38 

39from binascii import b2a_hex 

40 

41from Crypto.Hash import SHA256 

42 

43assert SHA256.digest_size == 32 

44 

45class _SHAd256(object): 

46 """SHA-256, doubled. 

47 

48 Returns SHA-256(SHA-256(data)). 

49 """ 

50 

51 digest_size = SHA256.digest_size 

52 

53 _internal = object() 

54 

55 def __init__(self, internal_api_check, sha256_hash_obj): 

56 if internal_api_check is not self._internal: 

57 raise AssertionError("Do not instantiate this class directly. Use %s.new()" % (__name__,)) 

58 self._h = sha256_hash_obj 

59 

60 # PEP 247 "copy" method 

61 def copy(self): 

62 """Return a copy of this hashing object""" 

63 return _SHAd256(SHAd256._internal, self._h.copy()) 

64 

65 # PEP 247 "digest" method 

66 def digest(self): 

67 """Return the hash value of this object as a binary string""" 

68 retval = SHA256.new(self._h.digest()).digest() 

69 assert len(retval) == 32 

70 return retval 

71 

72 # PEP 247 "hexdigest" method 

73 def hexdigest(self): 

74 """Return the hash value of this object as a (lowercase) hexadecimal string""" 

75 retval = b2a_hex(self.digest()) 

76 assert len(retval) == 64 

77 if sys.version_info[0] == 2: 

78 return retval 

79 else: 

80 return retval.decode() 

81 

82 # PEP 247 "update" method 

83 def update(self, data): 

84 self._h.update(data) 

85 

86# PEP 247 module-level "digest_size" variable 

87digest_size = _SHAd256.digest_size 

88 

89# PEP 247 module-level "new" function 

90def new(data=None): 

91 """Return a new SHAd256 hashing object""" 

92 if not data: 

93 data=b("") 

94 sha = _SHAd256(_SHAd256._internal, SHA256.new(data)) 

95 sha.new = globals()['new'] 

96 return sha 

97 

98# vim:set ts=4 sw=4 sts=4 expandtab: