pqc/crypto_sign/sphincs-shake256-192s-simple/clean/hash_shake256.c
Thom Wiggers 74efb10807
Incorporate feedback
* Names passed around (mostly constant) value more clearly
* Put ``const`` where applicable (almost everywhere)
* Renamed ``primitive.h``
* Fixed some nits
2019-07-17 08:37:38 +02:00

99 lines
3.5 KiB
C

#include <stdint.h>
#include <string.h>
#include "address.h"
#include "hash.h"
#include "params.h"
#include "utils.h"
#include "fips202.h"
/* For SHAKE256, there is no immediate reason to initialize at the start,
so this function is an empty operation. */
void PQCLEAN_SPHINCSSHAKE256192SSIMPLE_CLEAN_initialize_hash_function(
hash_state *hash_state_seeded,
const unsigned char *pub_seed, const unsigned char *sk_seed) {
(void)hash_state_seeded; /* Suppress an 'unused parameter' warning. */
(void)pub_seed; /* Suppress an 'unused parameter' warning. */
(void)sk_seed; /* Suppress an 'unused parameter' warning. */
}
/*
* Computes PRF(key, addr), given a secret key of SPX_N bytes and an address
*/
void PQCLEAN_SPHINCSSHAKE256192SSIMPLE_CLEAN_prf_addr(
unsigned char *out, const unsigned char *key, const uint32_t addr[8],
const hash_state *hash_state_seeded) {
unsigned char buf[SPX_N + SPX_ADDR_BYTES];
memcpy(buf, key, SPX_N);
PQCLEAN_SPHINCSSHAKE256192SSIMPLE_CLEAN_addr_to_bytes(buf + SPX_N, addr);
shake256(out, SPX_N, buf, SPX_N + SPX_ADDR_BYTES);
(void)hash_state_seeded; /* Prevent unused parameter warning. */
}
/**
* Computes the message-dependent randomness R, using a secret seed and an
* optional randomization value as well as the message.
*/
void PQCLEAN_SPHINCSSHAKE256192SSIMPLE_CLEAN_gen_message_random(
unsigned char *R,
const unsigned char *sk_prf, const unsigned char *optrand,
const unsigned char *m, size_t mlen,
const hash_state *hash_state_seeded) {
shake256incctx state;
shake256_inc_init(&state);
shake256_inc_absorb(&state, sk_prf, SPX_N);
shake256_inc_absorb(&state, optrand, SPX_N);
shake256_inc_absorb(&state, m, mlen);
shake256_inc_finalize(&state);
shake256_inc_squeeze(R, SPX_N, &state);
(void)hash_state_seeded; /* Prevent unused parameter warning. */
}
/**
* Computes the message hash using R, the public key, and the message.
* Outputs the message digest and the index of the leaf. The index is split in
* the tree index and the leaf index, for convenient copying to an address.
*/
void PQCLEAN_SPHINCSSHAKE256192SSIMPLE_CLEAN_hash_message(
unsigned char *digest, uint64_t *tree, uint32_t *leaf_idx,
const unsigned char *R, const unsigned char *pk,
const unsigned char *m, size_t mlen,
const hash_state *hash_state_seeded) {
#define SPX_TREE_BITS (SPX_TREE_HEIGHT * (SPX_D - 1))
#define SPX_TREE_BYTES ((SPX_TREE_BITS + 7) / 8)
#define SPX_LEAF_BITS SPX_TREE_HEIGHT
#define SPX_LEAF_BYTES ((SPX_LEAF_BITS + 7) / 8)
#define SPX_DGST_BYTES (SPX_FORS_MSG_BYTES + SPX_TREE_BYTES + SPX_LEAF_BYTES)
unsigned char buf[SPX_DGST_BYTES];
unsigned char *bufp = buf;
shake256incctx state;
shake256_inc_init(&state);
shake256_inc_absorb(&state, R, SPX_N);
shake256_inc_absorb(&state, pk, SPX_PK_BYTES);
shake256_inc_absorb(&state, m, mlen);
shake256_inc_finalize(&state);
shake256_inc_squeeze(buf, SPX_DGST_BYTES, &state);
memcpy(digest, bufp, SPX_FORS_MSG_BYTES);
bufp += SPX_FORS_MSG_BYTES;
*tree = PQCLEAN_SPHINCSSHAKE256192SSIMPLE_CLEAN_bytes_to_ull(
bufp, SPX_TREE_BYTES);
*tree &= (~(uint64_t)0) >> (64 - SPX_TREE_BITS);
bufp += SPX_TREE_BYTES;
*leaf_idx = (uint32_t)PQCLEAN_SPHINCSSHAKE256192SSIMPLE_CLEAN_bytes_to_ull(
bufp, SPX_LEAF_BYTES);
*leaf_idx &= (~(uint32_t)0) >> (32 - SPX_LEAF_BITS);
(void)hash_state_seeded; /* Prevent unused parameter warning. */
}