# Copyright (c) 2021 Pieter Wuille
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
"""Test-only pure Python RIPEMD160 implementation."""
# Message schedule indexes for the left path.
ML = [
0,
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13,
14,
15,
7,
4,
13,
1,
10,
6,
15,
3,
12,
0,
9,
5,
2,
14,
11,
8,
3,
10,
14,
4,
9,
15,
8,
1,
2,
7,
0,
6,
13,
11,
5,
12,
1,
9,
11,
10,
0,
8,
12,
4,
13,
3,
7,
15,
14,
5,
6,
2,
4,
0,
5,
9,
7,
12,
2,
10,
14,
1,
3,
8,
11,
6,
15,
13,
]
# Message schedule indexes for the right path.
MR = [
5,
14,
7,
0,
9,
2,
11,
4,
13,
6,
15,
8,
1,
10,
3,
12,
6,
11,
3,
7,
0,
13,
5,
10,
14,
15,
8,
12,
4,
9,
1,
2,
15,
5,
1,
3,
7,
14,
6,
9,
11,
8,
12,
2,
10,
0,
4,
13,
8,
6,
4,
1,
3,
11,
15,
0,
5,
12,
2,
13,
9,
7,
10,
14,
12,
15,
10,
4,
1,
5,
8,
7,
6,
2,
13,
14,
0,
3,
9,
11,
]
# Rotation counts for the left path.
RL = [
11,
14,
15,
12,
5,
8,
7,
9,
11,
13,
14,
15,
6,
7,
9,
8,
7,
6,
8,
13,
11,
9,
7,
15,
7,
12,
15,
9,
11,
7,
13,
12,
11,
13,
6,
7,
14,
9,
13,
15,
14,
8,
13,
6,
5,
12,
7,
5,
11,
12,
14,
15,
14,
15,
9,
8,
9,
14,
5,
6,
8,
6,
5,
12,
9,
15,
5,
11,
6,
8,
13,
12,
5,
12,
13,
14,
11,
8,
5,
6,
]
# Rotation counts for the right path.
RR = [
8,
9,
9,
11,
13,
15,
15,
5,
7,
7,
8,
11,
14,
14,
12,
6,
9,
13,
15,
7,
12,
8,
9,
11,
7,
7,
12,
7,
6,
15,
13,
11,
9,
7,
15,
11,
8,
6,
6,
14,
12,
13,
5,
14,
13,
13,
7,
5,
15,
5,
8,
11,
14,
14,
6,
14,
6,
9,
12,
9,
12,
5,
15,
8,
8,
5,
12,
9,
12,
5,
14,
6,
8,
13,
6,
5,
15,
13,
11,
11,
]
# K constants for the left path.
KL = [0, 0x5A827999, 0x6ED9EBA1, 0x8F1BBCDC, 0xA953FD4E]
# K constants for the right path.
KR = [0x50A28BE6, 0x5C4DD124, 0x6D703EF3, 0x7A6D76E9, 0]
def fi(x, y, z, i):
"""The f1, f2, f3, f4, and f5 functions from the specification."""
if i == 0:
return x ^ y ^ z
elif i == 1:
return (x & y) | (~x & z)
elif i == 2:
return (x | ~y) ^ z
elif i == 3:
return (x & z) | (y & ~z)
elif i == 4:
return x ^ (y | ~z)
else:
assert False
def rol(x, i):
"""Rotate the bottom 32 bits of x left by i bits."""
return ((x << i) | ((x & 0xFFFFFFFF) >> (32 - i))) & 0xFFFFFFFF
def compress(h0, h1, h2, h3, h4, block):
"""Compress state (h0, h1, h2, h3, h4) with block."""
# Left path variables.
al, bl, cl, dl, el = h0, h1, h2, h3, h4
# Right path variables.
ar, br, cr, dr, er = h0, h1, h2, h3, h4
# Message variables.
x = [int.from_bytes(block[4 * i : 4 * (i + 1)], "little") for i in range(16)]
# Iterate over the 80 rounds of the compression.
for j in range(80):
rnd = j >> 4
# Perform left side of the transformation.
al = rol(al + fi(bl, cl, dl, rnd) + x[ML[j]] + KL[rnd], RL[j]) + el
al, bl, cl, dl, el = el, al, bl, rol(cl, 10), dl
# Perform right side of the transformation.
ar = rol(ar + fi(br, cr, dr, 4 - rnd) + x[MR[j]] + KR[rnd], RR[j]) + er
ar, br, cr, dr, er = er, ar, br, rol(cr, 10), dr
# Compose old state, left transform, and right transform into new state.
return h1 + cl + dr, h2 + dl + er, h3 + el + ar, h4 + al + br, h0 + bl + cr
def ripemd160(data):
"""Compute the RIPEMD-160 hash of data."""
# Initialize state.
state = (0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476, 0xC3D2E1F0)
# Process full 64-byte blocks in the input.
for b in range(len(data) >> 6):
state = compress(*state, data[64 * b : 64 * (b + 1)])
# Construct final blocks (with padding and size).
pad = b"\x80" + b"\x00" * ((119 - len(data)) & 63)
fin = data[len(data) & ~63 :] + pad + (8 * len(data)).to_bytes(8, "little")
# Process final blocks.
for b in range(len(fin) >> 6):
state = compress(*state, fin[64 * b : 64 * (b + 1)])
# Produce output.
return b"".join((h & 0xFFFFFFFF).to_bytes(4, "little") for h in state)