Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/Crypto/Hash/__init__.py: 42%

1# -*- coding: utf-8 -*- 

2# 

3# =================================================================== 

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

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

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

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

8# contents of this file for any purpose whatsoever. 

9# No rights are reserved. 

10# 

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

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

13# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 

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

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

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

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

18# SOFTWARE. 

19# =================================================================== 

20 

21"""Hashing algorithms 

22 

23Hash functions take arbitrary binary strings as input, and produce a random-like output 

24of fixed size that is dependent on the input; it should be practically infeasible  

25to derive the original input data given only the hash function's 

26output. In other words, the hash function is *one-way*. 

27 

28It should also not be practically feasible to find a second piece of data 

29(a *second pre-image*) whose hash is the same as the original message 

30(*weak collision resistance*). 

31 

32Finally, it should not be feasible to find two arbitrary messages with the 

33same hash (*strong collision resistance*). 

34 

35The output of the hash function is called the *digest* of the input message. 

36In general, the security of a hash function is related to the length of the 

37digest. If the digest is *n* bits long, its security level is roughly comparable 

38to the the one offered by an *n/2* bit encryption algorithm. 

39 

40Hash functions can be used simply as a integrity check, or, in 

41association with a public-key algorithm, can be used to implement 

42digital signatures. 

43 

44The hashing modules here all support the interface described in `PEP 

45247`_ , "API for Cryptographic Hash Functions".  

46 

47.. _`PEP 247` : http://www.python.org/dev/peps/pep-0247/ 

48 

49:undocumented: _MD2, _MD4, _RIPEMD160, _SHA224, _SHA256, _SHA384, _SHA512 

50""" 

51 

52__all__ = ['HMAC', 'MD2', 'MD4', 'MD5', 'RIPEMD160', 'SHA1', 

53 'SHA224', 'SHA256', 'SHA384', 'SHA512', 'CMAC'] 

54 

55__revision__ = "$Id$" 

56 

57import sys 

58if sys.version_info[0] == 2 and sys.version_info[1] == 1: 

59 from Crypto.Util.py21compat import * 

60from Crypto.Util.py3compat import * 

61 

62def new(algo, *args): 

63 """Initialize a new hash object. 

64 

65 The first argument to this function may be an algorithm name or another 

66 hash object. 

67 

68 This function has significant overhead. It's recommended that you instead 

69 import and use the individual hash modules directly. 

70 """ 

71 

72 # Try just invoking algo.new() 

73 # We do this first so that this is the fastest. 

74 try: 

75 new_func = algo.new 

76 except AttributeError: 

77 pass 

78 else: 

79 return new_func(*args) 

80 

81 # Try getting the algorithm name. 

82 if isinstance(algo, str): 

83 name = algo 

84 else: 

85 try: 

86 name = algo.name 

87 except AttributeError: 

88 raise ValueError("unsupported hash type %r" % (algo,)) 

89 

90 # Got the name. Let's see if we have a PyCrypto implementation. 

91 try: 

92 new_func = _new_funcs[name] 

93 except KeyError: 

94 # No PyCrypto implementation. Try hashlib. 

95 try: 

96 import hashlib 

97 except ImportError: 

98 # There is no hashlib. 

99 raise ValueError("unsupported hash type %s" % (name,)) 

100 return hashlib.new(name, *args) 

101 else: 

102 # We have a PyCrypto implementation. Instantiate it. 

103 return new_func(*args) 

104 

105# This dict originally gets the following _*_new methods, but its members get 

106# replaced with the real new() methods of the various hash modules as they are 

107# used. We do it without locks to improve performance, which is safe in 

108# CPython because dict access is atomic in CPython. This might break PyPI. 

109_new_funcs = {} 

110 

111def _md2_new(*args): 

112 from Crypto.Hash import MD2 

113 _new_funcs['MD2'] = _new_funcs['md2'] = MD2.new 

114 return MD2.new(*args) 

115_new_funcs['MD2'] = _new_funcs['md2'] = _md2_new 

116del _md2_new 

117 

118def _md4_new(*args): 

119 from Crypto.Hash import MD4 

120 _new_funcs['MD4'] = _new_funcs['md4'] = MD4.new 

121 return MD4.new(*args) 

122_new_funcs['MD4'] = _new_funcs['md4'] = _md4_new 

123del _md4_new 

124 

125def _md5_new(*args): 

126 from Crypto.Hash import MD5 

127 _new_funcs['MD5'] = _new_funcs['md5'] = MD5.new 

128 return MD5.new(*args) 

129_new_funcs['MD5'] = _new_funcs['md5'] = _md5_new 

130del _md5_new 

131 

132def _ripemd160_new(*args): 

133 from Crypto.Hash import RIPEMD160 

134 _new_funcs['RIPEMD160'] = _new_funcs['ripemd160'] = \ 

135 _new_funcs['RIPEMD'] = _new_funcs['ripemd'] = RIPEMD160.new 

136 return RIPEMD160.new(*args) 

137_new_funcs['RIPEMD160'] = _new_funcs['ripemd160'] = \ 

138 _new_funcs['RIPEMD'] = _new_funcs['ripemd'] = _ripemd160_new 

139del _ripemd160_new 

140 

141def _sha1_new(*args): 

142 from Crypto.Hash import SHA1 

143 _new_funcs['SHA1'] = _new_funcs['sha1'] = \ 

144 _new_funcs['SHA'] = _new_funcs['sha'] = SHA1.new 

145 return SHA1.new(*args) 

146_new_funcs['SHA1'] = _new_funcs['sha1'] = \ 

147 _new_funcs['SHA'] = _new_funcs['sha'] = _sha1_new 

148del _sha1_new 

149 

150def _sha224_new(*args): 

151 from Crypto.Hash import SHA224 

152 _new_funcs['SHA224'] = _new_funcs['sha224'] = SHA224.new 

153 return SHA224.new(*args) 

154_new_funcs['SHA224'] = _new_funcs['sha224'] = _sha224_new 

155del _sha224_new 

156 

157def _sha256_new(*args): 

158 from Crypto.Hash import SHA256 

159 _new_funcs['SHA256'] = _new_funcs['sha256'] = SHA256.new 

160 return SHA256.new(*args) 

161_new_funcs['SHA256'] = _new_funcs['sha256'] = _sha256_new 

162del _sha256_new 

163 

164def _sha384_new(*args): 

165 from Crypto.Hash import SHA384 

166 _new_funcs['SHA384'] = _new_funcs['sha384'] = SHA384.new 

167 return SHA384.new(*args) 

168_new_funcs['SHA384'] = _new_funcs['sha384'] = _sha384_new 

169del _sha384_new 

170 

171def _sha512_new(*args): 

172 from Crypto.Hash import SHA512 

173 _new_funcs['SHA512'] = _new_funcs['sha512'] = SHA512.new 

174 return SHA512.new(*args) 

175_new_funcs['SHA512'] = _new_funcs['sha512'] = _sha512_new 

176del _sha512_new