chanserv/batcher/sha256.py

   1 #!/usr/bin/python
   2 __author__ = 'Thomas Dixon'
   3 __license__ = 'MIT'
   4
   5 import copy, struct, sys
   6
   7 def new(m=None):
   8     return sha256(m)
   9
  10 class sha256(object):
  11     _k = (0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
  12           0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
  13           0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
  14           0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
  15           0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
  16           0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
  17           0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
  18           0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
  19           0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
  20           0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
  21           0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
  22           0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
  23           0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
  24           0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
  25           0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
  26           0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2)
  27     _h = (0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
  28           0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19)
  29     _output_size = 8
  30
  31     blocksize = 1
  32     digest_size = 32
  33
  34     def __init__(self, m=None):
  35         self._buffer = ''
  36         self._counter = 0
  37
  38         if m is not None:
  39             if type(m) is not str:
  40                 raise TypeError, '%s() argument 1 must be string, not %s' % (self.__class__.__name__, type(m).__name__)
  41             self.update(m)
  42
  43     def _rotr(self, x, y):
  44         return ((x >> y) | (x << (32-y))) & 0xFFFFFFFF
  45
  46     def _sha256_process(self, c):
  47         w = [0]*64
  48         w[0:15] = struct.unpack('!16L', c)
  49
  50         for i in range(16, 64):
  51             s0 = self._rotr(w[i-15], 7) ^ self._rotr(w[i-15], 18) ^ (w[i-15] >> 3)
  52             s1 = self._rotr(w[i-2], 17) ^ self._rotr(w[i-2], 19) ^ (w[i-2] >> 10)
  53             w[i] = (w[i-16] + s0 + w[i-7] + s1) & 0xFFFFFFFF
  54
  55         a,b,c,d,e,f,g,h = self._h
  56
  57         for i in range(64):
  58             s0 = self._rotr(a, 2) ^ self._rotr(a, 13) ^ self._rotr(a, 22)
  59             maj = (a & b) ^ (a & c) ^ (b & c)
  60             t2 = s0 + maj
  61             s1 = self._rotr(e, 6) ^ self._rotr(e, 11) ^ self._rotr(e, 25)
  62             ch = (e & f) ^ ((~e) & g)
  63             t1 = h + s1 + ch + self._k[i] + w[i]
  64
  65             h = g
  66             g = f
  67             f = e
  68             e = (d + t1) & 0xFFFFFFFF
  69             d = c
  70             c = b
  71             b = a
  72             a = (t1 + t2) & 0xFFFFFFFF
  73
  74         self._h = [(x+y) & 0xFFFFFFFF for x,y in zip(self._h, [a,b,c,d,e,f,g,h])]
  75
  76     def update(self, m):
  77         if not m:
  78             return
  79         if type(m) is not str:
  80             raise TypeError, '%s() argument 1 must be string, not %s' % (sys._getframe().f_code.co_name, type(m).__name__)
  81
  82         self._buffer += m
  83         self._counter += len(m)
  84
  85         while len(self._buffer) >= 64:
  86             self._sha256_process(self._buffer[:64])
  87             self._buffer = self._buffer[64:]
  88
  89     def digest(self):
  90         mdi = self._counter & 0x3F
  91         length = struct.pack('!Q', self._counter<<3)
  92
  93         if mdi < 56:
  94             padlen = 55-mdi
  95         else:
  96             padlen = 119-mdi
  97
  98         r = self.copy()
  99         r.update('\x80'+('\x00'*padlen)+length)
 100         return ''.join([struct.pack('!L', i) for i in r._h[:self._output_size]])
 101
 102     def hexdigest(self):
 103         return self.digest().encode('hex')
 104
 105     def copy(self):
 106         return copy.deepcopy(self)
 107
 108 digest_size = new().digest_size