pqc/crypto_sign/sphincs-sha256-256s-robust/clean/thash_sha256_robust.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

83 lines
2.9 KiB
C

#include <stdint.h>
#include <string.h>
#include "address.h"
#include "params.h"
#include "thash.h"
#include "sha2.h"
#include "sha256.h"
/**
* Takes an array of inblocks concatenated arrays of SPX_N bytes.
*/
static void PQCLEAN_SPHINCSSHA256256SROBUST_CLEAN_thash(
unsigned char *out, unsigned char *buf,
const unsigned char *in, unsigned int inblocks,
const unsigned char *pub_seed, uint32_t addr[8],
const sha256ctx *hash_state_seeded) {
unsigned char outbuf[SPX_SHA256_OUTPUT_BYTES];
unsigned char *bitmask = buf + SPX_N + SPX_SHA256_ADDR_BYTES + 4;
sha256ctx sha2_state;
unsigned int i;
memcpy(buf, pub_seed, SPX_N);
PQCLEAN_SPHINCSSHA256256SROBUST_CLEAN_compress_address(buf + SPX_N, addr);
/* MGF1 requires us to have 4 extra bytes in 'buf' */
PQCLEAN_SPHINCSSHA256256SROBUST_CLEAN_mgf1(bitmask, inblocks * SPX_N, buf, SPX_N + SPX_SHA256_ADDR_BYTES);
/* Retrieve precomputed state containing pub_seed */
memcpy(&sha2_state, hash_state_seeded, sizeof(sha256ctx));
for (i = 0; i < inblocks * SPX_N; i++) {
buf[SPX_N + SPX_SHA256_ADDR_BYTES + i] = in[i] ^ bitmask[i];
}
sha256_inc_finalize(outbuf, &sha2_state, buf + SPX_N,
SPX_SHA256_ADDR_BYTES + inblocks * SPX_N);
memcpy(out, outbuf, SPX_N);
}
/* The wrappers below ensure that we use fixed-size buffers on the stack */
void PQCLEAN_SPHINCSSHA256256SROBUST_CLEAN_thash_1(
unsigned char *out, const unsigned char *in,
const unsigned char *pub_seed, uint32_t addr[8],
const sha256ctx *hash_state_seeded) {
unsigned char buf[SPX_N + SPX_SHA256_ADDR_BYTES + 4 + 1 * SPX_N];
PQCLEAN_SPHINCSSHA256256SROBUST_CLEAN_thash(
out, buf, in, 1, pub_seed, addr, hash_state_seeded);
}
void PQCLEAN_SPHINCSSHA256256SROBUST_CLEAN_thash_2(
unsigned char *out, const unsigned char *in,
const unsigned char *pub_seed, uint32_t addr[8],
const sha256ctx *hash_state_seeded) {
unsigned char buf[SPX_N + SPX_SHA256_ADDR_BYTES + 4 + 2 * SPX_N];
PQCLEAN_SPHINCSSHA256256SROBUST_CLEAN_thash(
out, buf, in, 2, pub_seed, addr, hash_state_seeded);
}
void PQCLEAN_SPHINCSSHA256256SROBUST_CLEAN_thash_WOTS_LEN(
unsigned char *out, const unsigned char *in,
const unsigned char *pub_seed, uint32_t addr[8],
const sha256ctx *hash_state_seeded) {
unsigned char buf[SPX_N + SPX_SHA256_ADDR_BYTES + 4 + SPX_WOTS_LEN * SPX_N];
PQCLEAN_SPHINCSSHA256256SROBUST_CLEAN_thash(
out, buf, in, SPX_WOTS_LEN, pub_seed, addr, hash_state_seeded);
}
void PQCLEAN_SPHINCSSHA256256SROBUST_CLEAN_thash_FORS_TREES(
unsigned char *out, const unsigned char *in,
const unsigned char *pub_seed, uint32_t addr[8],
const sha256ctx *hash_state_seeded) {
unsigned char buf[SPX_N + SPX_SHA256_ADDR_BYTES + 4 + SPX_FORS_TREES * SPX_N];
PQCLEAN_SPHINCSSHA256256SROBUST_CLEAN_thash(
out, buf, in, SPX_FORS_TREES, pub_seed, addr, hash_state_seeded);
}