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test/functional/test_framework/muhash.py
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#!/usr/bin/env python3 | |||||
# Copyright (c) 2020 Pieter Wuille | |||||
# Distributed under the MIT software license, see the accompanying | |||||
# file COPYING or http://www.opensource.org/licenses/mit-license.php. | |||||
"""Native Python MuHash3072 implementation.""" | |||||
import hashlib | |||||
import unittest | |||||
from .util import modinv | |||||
def rot32(v, bits): | |||||
"""Rotate the 32-bit value v left by bits bits.""" | |||||
# Make sure the term below does not throw an exception | |||||
bits %= 32 | |||||
return ((v << bits) & 0xffffffff) | (v >> (32 - bits)) | |||||
def chacha20_doubleround(s): | |||||
"""Apply a ChaCha20 double round to 16-element state array s. | |||||
See https://cr.yp.to/chacha/chacha-20080128.pdf and | |||||
https://tools.ietf.org/html/rfc8439 | |||||
""" | |||||
QUARTER_ROUNDS = [(0, 4, 8, 12), | |||||
(1, 5, 9, 13), | |||||
(2, 6, 10, 14), | |||||
(3, 7, 11, 15), | |||||
(0, 5, 10, 15), | |||||
(1, 6, 11, 12), | |||||
(2, 7, 8, 13), | |||||
(3, 4, 9, 14)] | |||||
for a, b, c, d in QUARTER_ROUNDS: | |||||
s[a] = (s[a] + s[b]) & 0xffffffff | |||||
s[d] = rot32(s[d] ^ s[a], 16) | |||||
s[c] = (s[c] + s[d]) & 0xffffffff | |||||
s[b] = rot32(s[b] ^ s[c], 12) | |||||
s[a] = (s[a] + s[b]) & 0xffffffff | |||||
s[d] = rot32(s[d] ^ s[a], 8) | |||||
s[c] = (s[c] + s[d]) & 0xffffffff | |||||
s[b] = rot32(s[b] ^ s[c], 7) | |||||
def chacha20_32_to_384(key32): | |||||
"""Specialized ChaCha20 implementation with 32-byte key, 0 IV, | |||||
384-byte output.""" | |||||
# See RFC 8439 section 2.3 for chacha20 parameters | |||||
CONSTANTS = [0x61707865, 0x3320646e, 0x79622d32, 0x6b206574] | |||||
key_bytes = [0] * 8 | |||||
for i in range(8): | |||||
key_bytes[i] = int.from_bytes(key32[(4 * i):(4 * (i + 1))], 'little') | |||||
INITIALIZATION_VECTOR = [0] * 4 | |||||
init = CONSTANTS + key_bytes + INITIALIZATION_VECTOR | |||||
out = bytearray() | |||||
for counter in range(6): | |||||
init[12] = counter | |||||
s = init.copy() | |||||
for _ in range(10): | |||||
chacha20_doubleround(s) | |||||
for i in range(16): | |||||
out.extend(((s[i] + init[i]) & 0xffffffff).to_bytes(4, 'little')) | |||||
return bytes(out) | |||||
def data_to_num3072(data): | |||||
"""Hash a 32-byte array data to a 3072-bit number using 6 Chacha20 | |||||
operations.""" | |||||
bytes384 = chacha20_32_to_384(data) | |||||
return int.from_bytes(bytes384, 'little') | |||||
class MuHash3072: | |||||
"""Class representing the MuHash3072 computation of a set. | |||||
See https://cseweb.ucsd.edu/~mihir/papers/inchash.pdf and | |||||
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-May/014337.html | |||||
""" | |||||
MODULUS = 2**3072 - 1103717 | |||||
def __init__(self): | |||||
"""Initialize for an empty set.""" | |||||
self.numerator = 1 | |||||
self.denominator = 1 | |||||
def insert(self, data): | |||||
"""Insert a byte array data in the set.""" | |||||
self.numerator = ( | |||||
self.numerator * data_to_num3072(data)) % self.MODULUS | |||||
def remove(self, data): | |||||
"""Remove a byte array from the set.""" | |||||
self.denominator = ( | |||||
self.denominator * data_to_num3072(data)) % self.MODULUS | |||||
def digest(self): | |||||
"""Extract the final hash. Does not modify this object.""" | |||||
val = (self.numerator * | |||||
modinv(self.denominator, self.MODULUS)) % self.MODULUS | |||||
bytes384 = val.to_bytes(384, 'little') | |||||
return hashlib.sha256(bytes384).digest() | |||||
class TestFrameworkMuhash(unittest.TestCase): | |||||
def test_muhash(self): | |||||
muhash = MuHash3072() | |||||
muhash.insert([0] * 32) | |||||
muhash.insert([1] + [0] * 31) | |||||
muhash.remove([2] + [0] * 31) | |||||
finalized = muhash.digest() | |||||
# This mirrors the result in the C++ MuHash3072 unit test | |||||
self.assertEqual( | |||||
finalized[::-1].hex(), | |||||
"a44e16d5e34d259b349af21c06e65d653915d2e208e4e03f389af750dc0bfdc3") | |||||
def test_chacha20(self): | |||||
def chacha_check(key, result): | |||||
self.assertEqual(chacha20_32_to_384(key)[:64].hex(), result) | |||||
# Test vectors from https://tools.ietf.org/html/draft-agl-tls-chacha20poly1305-04#section-7 | |||||
# Since the nonce is hardcoded to 0 in our function we only use those | |||||
# vectors. | |||||
chacha_check( | |||||
[0] * 32, | |||||
"76b8e0ada0f13d90405d6ae55386bd28bdd219b8a08ded1aa836efcc8b770dc7da41597c5157488d7724e03fb8d84a376a43b8f41518a11cc387b669b2ee6586") | |||||
chacha_check( | |||||
[0] * 31 + [1], | |||||
"4540f05a9f1fb296d7736e7b208e3c96eb4fe1834688d2604f450952ed432d41bbe2a0b6ea7566d2a5d1e7e20d42af2c53d792b1c43fea817e9ad275ae546963") |