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Pure python3 implementation of SHA256 based on @thomdixon's pysha2
#!/usr/bin/python3
__base__ = 'https://github.com/thomdixon/pysha2/blob/master/sha2/sha256.py'
__author__ = 'Lukas Prokop'
__license__ = 'MIT'
import copy
import struct
import binascii
F32 = 0xFFFFFFFF
_k = [0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2]
_h = [0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19]
def _pad(msglen):
mdi = msglen & 0x3F
length = struct.pack('!Q', msglen << 3)
if mdi < 56:
padlen = 55 - mdi
else:
padlen = 119 - mdi
return b'\x80' + (b'\x00' * padlen) + length
def _rotr(x, y):
return ((x >> y) | (x << (32 - y))) & F32
def _maj(x, y, z):
return (x & y) ^ (x & z) ^ (y & z)
def _ch(x, y, z):
return (x & y) ^ ((~x) & z)
class SHA256:
_output_size = 8
blocksize = 1
block_size = 64
digest_size = 32
def __init__(self, m=None):
self._counter = 0
self._cache = b''
self._k = copy.deepcopy(_k)
self._h = copy.deepcopy(_h)
self.update(m)
def _compress(self, c):
w = [0] * 64
w[0:16] = struct.unpack('!16L', c)
for i in range(16, 64):
s0 = _rotr(w[i-15], 7) ^ _rotr(w[i-15], 18) ^ (w[i-15] >> 3)
s1 = _rotr(w[i-2], 17) ^ _rotr(w[i-2], 19) ^ (w[i-2] >> 10)
w[i] = (w[i-16] + s0 + w[i-7] + s1) & F32
a, b, c, d, e, f, g, h = self._h
for i in range(64):
s0 = _rotr(a, 2) ^ _rotr(a, 13) ^ _rotr(a, 22)
t2 = s0 + _maj(a, b, c)
s1 = _rotr(e, 6) ^ _rotr(e, 11) ^ _rotr(e, 25)
t1 = h + s1 + _ch(e, f, g) + self._k[i] + w[i]
h = g
g = f
f = e
e = (d + t1) & F32
d = c
c = b
b = a
a = (t1 + t2) & F32
for i, (x, y) in enumerate(zip(self._h, [a, b, c, d, e, f, g, h])):
self._h[i] = (x + y) & F32
def update(self, m):
if not m:
return
self._counter += len(m)
m = self._cache + m
for i in range(0, len(m) // 64):
self._compress(m[64 * i:64 * (i + 1)])
self._cache = m[-(len(m) % 64):]
def digest(self):
r = copy.deepcopy(self)
r.update(_pad(self._counter))
data = [struct.pack('!L', i) for i in r._h[:self._output_size]]
return b''.join(data)
def hexdigest(self):
return binascii.hexlify(self.digest()).decode('ascii')
if __name__ == '__main__':
def check(msg, sig):
m = SHA256()
m.update(msg.encode('ascii'))
print(m.hexdigest() == sig)
tests = {
"":
'e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855',
"a":
'ca978112ca1bbdcafac231b39a23dc4da786eff8147c4e72b9807785afee48bb',
"abc":
'ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad',
"message digest":
'f7846f55cf23e14eebeab5b4e1550cad5b509e3348fbc4efa3a1413d393cb650',
"abcdefghijklmnopqrstuvwxyz":
'71c480df93d6ae2f1efad1447c66c9525e316218cf51fc8d9ed832f2daf18b73',
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789":
'db4bfcbd4da0cd85a60c3c37d3fbd8805c77f15fc6b1fdfe614ee0a7c8fdb4c0',
("12345678901234567890123456789012345678901234567890123456789"
"012345678901234567890"):
'f371bc4a311f2b009eef952dd83ca80e2b60026c8e935592d0f9c308453c813e'
}
for inp, out in tests.items():
check(inp, out)
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