193 lines
4 KiB
C++
193 lines
4 KiB
C++
/* Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
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*
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* This file is provided under a dual BSD/GPLv2 license.
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*
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* SipHash: a fast short-input PRF
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* https://131002.net/siphash/
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*
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* This implementation is specifically for SipHash2-4 for a secure PRF
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* and HalfSipHash1-3/SipHash1-3 for an insecure PRF only suitable for
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* hashtables.
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*/
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#include "stdafx.h"
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#include "crypto/siphash.h"
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#include "tunsafe_endian.h"
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#define SIPROUND \
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do { \
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v0 += v1; v1 = rol64(v1, 13); v1 ^= v0; v0 = rol64(v0, 32); \
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v2 += v3; v3 = rol64(v3, 16); v3 ^= v2; \
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v0 += v3; v3 = rol64(v3, 21); v3 ^= v0; \
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v2 += v1; v1 = rol64(v1, 17); v1 ^= v2; v2 = rol64(v2, 32); \
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} while (0)
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#define PREAMBLE(len) \
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uint64 v0 = 0x736f6d6570736575ULL; \
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uint64 v1 = 0x646f72616e646f6dULL; \
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uint64 v2 = 0x6c7967656e657261ULL; \
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uint64 v3 = 0x7465646279746573ULL; \
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uint64 b = ((uint64)(len)) << 56; \
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v3 ^= key->key[1]; \
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v2 ^= key->key[0]; \
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v1 ^= key->key[1]; \
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v0 ^= key->key[0];
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#define POSTAMBLE \
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v3 ^= b; \
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SIPROUND; \
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SIPROUND; \
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v0 ^= b; \
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v2 ^= 0xff; \
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SIPROUND; \
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SIPROUND; \
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SIPROUND; \
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SIPROUND; \
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return (v0 ^ v1) ^ (v2 ^ v3);
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uint64 siphash(const void *data, size_t len, const siphash_key_t *key) {
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const uint8 *end = (uint8*)data + len - (len % sizeof(uint64));
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const uint8 left = len & (sizeof(uint64) - 1);
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uint64 m;
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PREAMBLE(len)
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for (; data != end; data = (uint8*)data + sizeof(uint64)) {
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m = ReadLE64(data);
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v3 ^= m;
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SIPROUND;
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SIPROUND;
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v0 ^= m;
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}
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switch (left) {
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case 7: b |= ((uint64)end[6]) << 48;
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case 6: b |= ((uint64)end[5]) << 40;
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case 5: b |= ((uint64)end[4]) << 32;
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case 4: b |= ReadLE32(data); break;
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case 3: b |= ((uint64)end[2]) << 16;
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case 2: b |= ReadLE16(data); break;
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case 1: b |= end[0];
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}
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POSTAMBLE
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}
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/**
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* siphash_1u64 - compute 64-bit siphash PRF value of a uint64
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* @first: first uint64
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* @key: the siphash key
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*/
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uint64 siphash_1u64(const uint64 first, const siphash_key_t *key)
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{
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PREAMBLE(8)
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v3 ^= first;
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SIPROUND;
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SIPROUND;
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v0 ^= first;
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POSTAMBLE
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}
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/**
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* siphash_2u64 - compute 64-bit siphash PRF value of 2 uint64
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* @first: first uint64
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* @second: second uint64
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* @key: the siphash key
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*/
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uint64 siphash_2u64(const uint64 first, const uint64 second, const siphash_key_t *key)
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{
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PREAMBLE(16)
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v3 ^= first;
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SIPROUND;
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SIPROUND;
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v0 ^= first;
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v3 ^= second;
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SIPROUND;
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SIPROUND;
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v0 ^= second;
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POSTAMBLE
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}
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/**
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* siphash_3u64 - compute 64-bit siphash PRF value of 3 uint64
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* @first: first uint64
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* @second: second uint64
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* @third: third uint64
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* @key: the siphash key
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*/
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uint64 siphash_3u64(const uint64 first, const uint64 second, const uint64 third,
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const siphash_key_t *key)
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{
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PREAMBLE(24)
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v3 ^= first;
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SIPROUND;
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SIPROUND;
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v0 ^= first;
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v3 ^= second;
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SIPROUND;
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SIPROUND;
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v0 ^= second;
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v3 ^= third;
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SIPROUND;
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SIPROUND;
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v0 ^= third;
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POSTAMBLE
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}
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/**
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* siphash_4u64 - compute 64-bit siphash PRF value of 4 uint64
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* @first: first uint64
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* @second: second uint64
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* @third: third uint64
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* @forth: forth uint64
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* @key: the siphash key
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*/
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uint64 siphash_4u64(const uint64 first, const uint64 second, const uint64 third,
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const uint64 forth, const siphash_key_t *key)
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{
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PREAMBLE(32)
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v3 ^= first;
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SIPROUND;
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SIPROUND;
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v0 ^= first;
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v3 ^= second;
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SIPROUND;
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SIPROUND;
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v0 ^= second;
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v3 ^= third;
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SIPROUND;
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SIPROUND;
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v0 ^= third;
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v3 ^= forth;
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SIPROUND;
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SIPROUND;
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v0 ^= forth;
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POSTAMBLE
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}
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uint64 siphash_1u32(const uint32 first, const siphash_key_t *key)
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{
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PREAMBLE(4)
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b |= first;
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POSTAMBLE
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}
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uint64 siphash_3u32(const uint32 first, const uint32 second, const uint32 third,
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const siphash_key_t *key)
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{
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uint64 combined = (uint64)second << 32 | first;
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PREAMBLE(12)
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v3 ^= combined;
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SIPROUND;
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SIPROUND;
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v0 ^= combined;
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b |= third;
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POSTAMBLE
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}
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uint64 siphash_u64_u32(const uint64 combined, const uint32 third, const siphash_key_t *key) {
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PREAMBLE(12)
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v3 ^= combined;
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SIPROUND;
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SIPROUND;
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v0 ^= combined;
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b |= third;
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POSTAMBLE
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}
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