79 lines
2.8 KiB
Python
79 lines
2.8 KiB
Python
#! /usr/bin/python3
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import struct
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class SHA256:
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def __init__(self):
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self.h = [
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0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c,
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0x1f83d9ab, 0x5be0cd19
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]
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self.k = [
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0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
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0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
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0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
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0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
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0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
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0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
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0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
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0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
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0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
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0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
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0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
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]
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def rotate_right(self, v, n):
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w = (v >> n) | (v << (32 - n))
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return w & 0xffffffff
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def compression_step(self, state, k_i, w_i):
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a, b, c, d, e, f, g, h = state
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s1 = self.rotate_right(e, 6) ^ self.rotate_right(e, 11) ^ self.rotate_right(e, 25)
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ch = (e & f) ^ (~e & g)
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tmp1 = (h + s1 + ch + k_i + w_i) & 0xffffffff
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s0 = self.rotate_right(a, 2) ^ self.rotate_right(a, 13) ^ self.rotate_right(a, 22)
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maj = (a & b) ^ (a & c) ^ (b & c)
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tmp2 = (tmp1 + s0 + maj) & 0xffffffff
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tmp3 = (d + tmp1) & 0xffffffff
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return (tmp2, a, b, c, tmp3, e, f, g)
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def compression(self, state, w, round_keys = None):
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if round_keys is None:
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round_keys = self.k
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for i in range(64):
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state = self.compression_step(state, round_keys[i], w[i])
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return state
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def compute_w(self, m):
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w = list(struct.unpack('>16L', m))
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for _ in range(16, 64):
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a, b = w[-15], w[-2]
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s0 = self.rotate_right(a, 7) ^ self.rotate_right(a, 18) ^ (a >> 3)
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s1 = self.rotate_right(b, 17) ^ self.rotate_right(b, 19) ^ (b >> 10)
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s = (w[-16] + w[-7] + s0 + s1) & 0xffffffff
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w.append(s)
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return w
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def padding(self, m):
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lm = len(m)
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lpad = struct.pack('>Q', 8 * lm)
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lenz = -(lm + 9) % 64
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return m + bytes([0x80]) + bytes(lenz) + lpad
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def sha256_raw(self, m, round_keys = None):
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if len(m) % 64 != 0:
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raise ValueError('m must be a multiple of 64 bytes')
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state = self.h
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for i in range(0, len(m), 64):
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block = m[i:i + 64]
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w = self.compute_w(block)
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s = self.compression(state, w, round_keys)
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state = [(x + y) & 0xffffffff for x, y in zip(state, s)]
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return state
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def sha256(self, m, round_keys = None):
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m_padded = self.padding(m)
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state = self.sha256_raw(m_padded, round_keys)
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return struct.pack('>8L', *state)
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