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- /* Based on the public domain implementation in
- * crypto_hash/sha512/ref/ from http://bench.cr.yp.to/supercop.html
- * by D. J. Bernstein */
-
- #include <stddef.h>
- #include <stdint.h>
- #include <string.h>
-
- #include "sha2.h"
- #include "sha256.h"
- #include "utils.h"
-
- /*
- * Compresses an address to a 22-byte sequence.
- * This reduces the number of required SHA256 compression calls, as the last
- * block of input is padded with at least 65 bits.
- */
- void PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_compress_address(unsigned char *out, const uint32_t addr[8]) {
- PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(out, 1, addr[0]); /* drop 3 bytes of the layer field */
- PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(out + 1, 4, addr[2]); /* drop the highest tree address word */
- PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(out + 5, 4, addr[3]);
- PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(out + 9, 1, addr[4]); /* drop 3 bytes of the type field */
- PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(out + 10, 4, addr[5]);
- PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(out + 14, 4, addr[6]);
- PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(out + 18, 4, addr[7]);
- }
-
- /**
- * Requires 'input_plus_four_bytes' to have 'inlen' + 4 bytes, so that the last
- * four bytes can be used for the counter. Typically 'input' is merely a seed.
- * Outputs outlen number of bytes
- */
- void PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_mgf1(
- unsigned char *out, unsigned long outlen,
- unsigned char *input_plus_four_bytes, unsigned long inlen) {
- unsigned char outbuf[PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_SHA256_OUTPUT_BYTES];
- unsigned long i;
-
- /* While we can fit in at least another full block of SHA256 output.. */
- for (i = 0; (i + 1)*PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_SHA256_OUTPUT_BYTES <= outlen; i++) {
- PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(input_plus_four_bytes + inlen, 4, i);
- sha256(out, input_plus_four_bytes, inlen + 4);
- out += PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_SHA256_OUTPUT_BYTES;
- }
- /* Until we cannot anymore, and we fill the remainder. */
- if (outlen > i * PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_SHA256_OUTPUT_BYTES) {
- PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(input_plus_four_bytes + inlen, 4, i);
- sha256(outbuf, input_plus_four_bytes, inlen + 4);
- memcpy(out, outbuf, outlen - i * PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_SHA256_OUTPUT_BYTES);
- }
- }
-
-
- /**
- * Absorb the constant pub_seed using one round of the compression function
- * This initializes hash_state_seeded, which can then be reused in thash
- **/
- void PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_seed_state(sha256ctx *hash_state_seeded, const unsigned char *pub_seed) {
- uint8_t block[PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_SHA256_BLOCK_BYTES];
- size_t i;
-
- for (i = 0; i < PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_N; ++i) {
- block[i] = pub_seed[i];
- }
- for (i = PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_N; i < PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_SHA256_BLOCK_BYTES; ++i) {
- block[i] = 0;
- }
-
- sha256_inc_init(hash_state_seeded);
- sha256_inc_blocks(hash_state_seeded, block, 1);
- }
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