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siphash.c
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siphash.c
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/*
SipHash reference C implementation
Copyright (c) 2012-2021 Jean-Philippe Aumasson
Copyright (c) 2012-2014 Daniel J. Bernstein <[email protected]>
To the extent possible under law, the author(s) have dedicated all copyright
and related and neighboring rights to this software to the public domain
worldwide. This software is distributed without any warranty.
You should have received a copy of the CC0 Public Domain Dedication along
with
this software. If not, see
<http://creativecommons.org/publicdomain/zero/1.0/>.
*/
#include <assert.h>
#include <stdint.h>
#include <stddef.h>
/* default: SipHash-2-4 */
#ifndef cROUNDS
#define cROUNDS 2
#endif
#ifndef dROUNDS
#define dROUNDS 4
#endif
#define ROTL(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b))))
#define U32TO8_LE(p, v) \
(p)[0] = (uint8_t)((v)); \
(p)[1] = (uint8_t)((v) >> 8); \
(p)[2] = (uint8_t)((v) >> 16); \
(p)[3] = (uint8_t)((v) >> 24);
#define U64TO8_LE(p, v) \
U32TO8_LE((p), (uint32_t)((v))); \
U32TO8_LE((p) + 4, (uint32_t)((v) >> 32));
#define U8TO64_LE(p) \
(((uint64_t)((p)[0])) | ((uint64_t)((p)[1]) << 8) | \
((uint64_t)((p)[2]) << 16) | ((uint64_t)((p)[3]) << 24) | \
((uint64_t)((p)[4]) << 32) | ((uint64_t)((p)[5]) << 40) | \
((uint64_t)((p)[6]) << 48) | ((uint64_t)((p)[7]) << 56))
#define SIPROUND \
do { \
v0 += v1; \
v1 = ROTL(v1, 13); \
v1 ^= v0; \
v0 = ROTL(v0, 32); \
v2 += v3; \
v3 = ROTL(v3, 16); \
v3 ^= v2; \
v0 += v3; \
v3 = ROTL(v3, 21); \
v3 ^= v0; \
v2 += v1; \
v1 = ROTL(v1, 17); \
v1 ^= v2; \
v2 = ROTL(v2, 32); \
} while (0)
#ifdef DEBUG
#define TRACE \
#include <stdio.h>
do { \
printf("(%3zu) v0 %016" PRIx64 "\n", inlen, v0); \
printf("(%3zu) v1 %016" PRIx64 "\n", inlen, v1); \
printf("(%3zu) v2 %016" PRIx64 "\n", inlen, v2); \
printf("(%3zu) v3 %016" PRIx64 "\n", inlen, v3); \
} while (0)
#else
#define TRACE
#endif
int siphash(const void *in, const size_t inlen, const void *k, uint8_t *out,
const size_t outlen) {
const unsigned char *ni = (const unsigned char *)in;
const unsigned char *kk = (const unsigned char *)k;
assert((outlen == 8) || (outlen == 16));
uint64_t v0 = UINT64_C(0x736f6d6570736575);
uint64_t v1 = UINT64_C(0x646f72616e646f6d);
uint64_t v2 = UINT64_C(0x6c7967656e657261);
uint64_t v3 = UINT64_C(0x7465646279746573);
uint64_t k0 = U8TO64_LE(kk);
uint64_t k1 = U8TO64_LE(kk + 8);
uint64_t m;
int i;
const unsigned char *end = ni + inlen - (inlen % sizeof(uint64_t));
const int left = inlen & 7;
uint64_t b = ((uint64_t)inlen) << 56;
v3 ^= k1;
v2 ^= k0;
v1 ^= k1;
v0 ^= k0;
if (outlen == 16)
v1 ^= 0xee;
for (; ni != end; ni += 8) {
m = U8TO64_LE(ni);
v3 ^= m;
TRACE;
for (i = 0; i < cROUNDS; ++i)
SIPROUND;
v0 ^= m;
}
switch (left) {
case 7:
b |= ((uint64_t)ni[6]) << 48;
/* FALLTHRU */
case 6:
b |= ((uint64_t)ni[5]) << 40;
/* FALLTHRU */
case 5:
b |= ((uint64_t)ni[4]) << 32;
/* FALLTHRU */
case 4:
b |= ((uint64_t)ni[3]) << 24;
/* FALLTHRU */
case 3:
b |= ((uint64_t)ni[2]) << 16;
/* FALLTHRU */
case 2:
b |= ((uint64_t)ni[1]) << 8;
/* FALLTHRU */
case 1:
b |= ((uint64_t)ni[0]);
break;
case 0:
break;
}
v3 ^= b;
TRACE;
for (i = 0; i < cROUNDS; ++i)
SIPROUND;
v0 ^= b;
if (outlen == 16)
v2 ^= 0xee;
else
v2 ^= 0xff;
TRACE;
for (i = 0; i < dROUNDS; ++i)
SIPROUND;
b = v0 ^ v1 ^ v2 ^ v3;
U64TO8_LE(out, b);
if (outlen == 8)
return 0;
v1 ^= 0xdd;
TRACE;
for (i = 0; i < dROUNDS; ++i)
SIPROUND;
b = v0 ^ v1 ^ v2 ^ v3;
U64TO8_LE(out + 8, b);
return 0;
}