pqc/crypto_sign/falcon-1024/avx2/rng.c
2020-10-21 16:37:33 -04:00

196 lines
6.3 KiB
C

#include "inner.h"
#include <assert.h>
/*
* PRNG and interface to the system RNG.
*
* ==========================(LICENSE BEGIN)============================
*
* Copyright (c) 2017-2019 Falcon Project
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* ===========================(LICENSE END)=============================
*
* @author Thomas Pornin <thomas.pornin@nccgroup.com>
*/
/*
* Include relevant system header files. For Win32, this will also need
* linking with advapi32.dll, which we trigger with an appropriate #pragma.
*/
/* see inner.h */
int
PQCLEAN_FALCON1024_AVX2_get_seed(void *seed, size_t len) {
(void)seed;
if (len == 0) {
return 1;
}
return 0;
}
/* see inner.h */
void
PQCLEAN_FALCON1024_AVX2_prng_init(prng *p, inner_shake256_context *src) {
inner_shake256_extract(src, p->state.d, 56);
PQCLEAN_FALCON1024_AVX2_prng_refill(p);
}
/*
* PRNG based on ChaCha20.
*
* State consists in key (32 bytes) then IV (16 bytes) and block counter
* (8 bytes). Normally, we should not care about local endianness (this
* is for a PRNG), but for the NIST competition we need reproducible KAT
* vectors that work across architectures, so we enforce little-endian
* interpretation where applicable. Moreover, output words are "spread
* out" over the output buffer with the interleaving pattern that is
* naturally obtained from the AVX2 implementation that runs eight
* ChaCha20 instances in parallel.
*
* The block counter is XORed into the first 8 bytes of the IV.
*/
void
PQCLEAN_FALCON1024_AVX2_prng_refill(prng *p) {
static const uint32_t CW[] = {
0x61707865, 0x3320646e, 0x79622d32, 0x6b206574
};
uint64_t cc;
size_t u;
int i;
uint32_t *sw;
union {
uint32_t w[16];
__m256i y[2]; /* for alignment */
} t;
__m256i state[16], init[16];
sw = (uint32_t *)p->state.d;
/*
* XOR next counter values into state.
*/
cc = *(uint64_t *)(p->state.d + 48);
for (u = 0; u < 8; u ++) {
t.w[u] = (uint32_t)(cc + u);
t.w[u + 8] = (uint32_t)((cc + u) >> 32);
}
*(uint64_t *)(p->state.d + 48) = cc + 8;
/*
* Load state.
*/
for (u = 0; u < 4; u ++) {
state[u] = init[u] =
_mm256_broadcastd_epi32(_mm_cvtsi32_si128((int32_t)CW[u]));
}
for (u = 0; u < 10; u ++) {
state[u + 4] = init[u + 4] =
_mm256_broadcastd_epi32(_mm_cvtsi32_si128((int32_t)sw[u]));
}
state[14] = init[14] = _mm256_xor_si256(
_mm256_broadcastd_epi32(_mm_cvtsi32_si128((int32_t)sw[10])),
_mm256_loadu_si256((__m256i *)&t.w[0]));
state[15] = init[15] = _mm256_xor_si256(
_mm256_broadcastd_epi32(_mm_cvtsi32_si128((int32_t)sw[11])),
_mm256_loadu_si256((__m256i *)&t.w[8]));
/*
* Do all rounds.
*/
for (i = 0; i < 10; i ++) {
#define QROUND(a, b, c, d) do { \
state[a] = _mm256_add_epi32(state[a], state[b]); \
state[d] = _mm256_xor_si256(state[d], state[a]); \
state[d] = _mm256_or_si256( \
_mm256_slli_epi32(state[d], 16), \
_mm256_srli_epi32(state[d], 16)); \
state[c] = _mm256_add_epi32(state[c], state[d]); \
state[b] = _mm256_xor_si256(state[b], state[c]); \
state[b] = _mm256_or_si256( \
_mm256_slli_epi32(state[b], 12), \
_mm256_srli_epi32(state[b], 20)); \
state[a] = _mm256_add_epi32(state[a], state[b]); \
state[d] = _mm256_xor_si256(state[d], state[a]); \
state[d] = _mm256_or_si256( \
_mm256_slli_epi32(state[d], 8), \
_mm256_srli_epi32(state[d], 24)); \
state[c] = _mm256_add_epi32(state[c], state[d]); \
state[b] = _mm256_xor_si256(state[b], state[c]); \
state[b] = _mm256_or_si256( \
_mm256_slli_epi32(state[b], 7), \
_mm256_srli_epi32(state[b], 25)); \
} while (0)
QROUND( 0, 4, 8, 12);
QROUND( 1, 5, 9, 13);
QROUND( 2, 6, 10, 14);
QROUND( 3, 7, 11, 15);
QROUND( 0, 5, 10, 15);
QROUND( 1, 6, 11, 12);
QROUND( 2, 7, 8, 13);
QROUND( 3, 4, 9, 14);
#undef QROUND
}
/*
* Add initial state back and encode the result in the destination
* buffer. We can dump the AVX2 values "as is" because the non-AVX2
* code uses a compatible order of values.
*/
for (u = 0; u < 16; u ++) {
_mm256_storeu_si256((__m256i *)&p->buf.d[u << 5],
_mm256_add_epi32(state[u], init[u]));
}
p->ptr = 0;
}
/* see inner.h */
void
PQCLEAN_FALCON1024_AVX2_prng_get_bytes(prng *p, void *dst, size_t len) {
uint8_t *buf;
buf = dst;
while (len > 0) {
size_t clen;
clen = (sizeof p->buf.d) - p->ptr;
if (clen > len) {
clen = len;
}
memcpy(buf, p->buf.d, clen);
buf += clen;
len -= clen;
p->ptr += clen;
if (p->ptr == sizeof p->buf.d) {
PQCLEAN_FALCON1024_AVX2_prng_refill(p);
}
}
}