Implement SipHash in Python

This commit is contained in:
Pieter Wuille 2016-06-27 16:06:17 +02:00 committed by Suhas Daftuar
parent 56c87e9211
commit 9c8593d2b4
2 changed files with 68 additions and 0 deletions

View file

@ -0,0 +1,64 @@
#!/usr/bin/env python3
# Copyright (c) 2016 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
#
# siphash.py - Specialized SipHash-2-4 implementations
#
# This implements SipHash-2-4 for 256-bit integers.
def rotl64(n, b):
return n >> (64 - b) | (n & ((1 << (64 - b)) - 1)) << b
def siphash_round(v0, v1, v2, v3):
v0 = (v0 + v1) & ((1 << 64) - 1)
v1 = rotl64(v1, 13)
v1 ^= v0
v0 = rotl64(v0, 32)
v2 = (v2 + v3) & ((1 << 64) - 1)
v3 = rotl64(v3, 16)
v3 ^= v2
v0 = (v0 + v3) & ((1 << 64) - 1)
v3 = rotl64(v3, 21)
v3 ^= v0
v2 = (v2 + v1) & ((1 << 64) - 1)
v1 = rotl64(v1, 17)
v1 ^= v2
v2 = rotl64(v2, 32)
return (v0, v1, v2, v3)
def siphash256(k0, k1, h):
n0 = h & ((1 << 64) - 1)
n1 = (h >> 64) & ((1 << 64) - 1)
n2 = (h >> 128) & ((1 << 64) - 1)
n3 = (h >> 192) & ((1 << 64) - 1)
v0 = 0x736f6d6570736575 ^ k0
v1 = 0x646f72616e646f6d ^ k1
v2 = 0x6c7967656e657261 ^ k0
v3 = 0x7465646279746573 ^ k1 ^ n0
v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
v0 ^= n0
v3 ^= n1
v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
v0 ^= n1
v3 ^= n2
v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
v0 ^= n2
v3 ^= n3
v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
v0 ^= n3
v3 ^= 0x2000000000000000
v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
v0 ^= 0x2000000000000000
v2 ^= 0xFF
v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
return v0 ^ v1 ^ v2 ^ v3

View file

@ -122,6 +122,10 @@ BOOST_AUTO_TEST_CASE(siphash)
hasher3.Write(uint64_t(x)|(uint64_t(x+1)<<8)|(uint64_t(x+2)<<16)|(uint64_t(x+3)<<24)|
(uint64_t(x+4)<<32)|(uint64_t(x+5)<<40)|(uint64_t(x+6)<<48)|(uint64_t(x+7)<<56));
}
CHashWriter ss(SER_DISK, CLIENT_VERSION);
ss << CTransaction();
BOOST_CHECK_EQUAL(SipHashUint256(1, 2, ss.GetHash()), 0x79751e980c2a0a35ULL);
}
BOOST_AUTO_TEST_SUITE_END()