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https://github.com/henrydcase/pqc.git
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74efb10807
* Names passed around (mostly constant) value more clearly * Put ``const`` where applicable (almost everywhere) * Renamed ``primitive.h`` * Fixed some nits
72 lines
2.8 KiB
C
72 lines
2.8 KiB
C
/* Based on the public domain implementation in
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* crypto_hash/sha512/ref/ from http://bench.cr.yp.to/supercop.html
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* by D. J. Bernstein */
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#include <stddef.h>
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#include <stdint.h>
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#include <string.h>
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#include "sha2.h"
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#include "sha256.h"
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#include "utils.h"
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/*
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* Compresses an address to a 22-byte sequence.
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* This reduces the number of required SHA256 compression calls, as the last
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* block of input is padded with at least 65 bits.
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*/
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void PQCLEAN_SPHINCSSHA256128SROBUST_CLEAN_compress_address(unsigned char *out, const uint32_t addr[8]) {
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PQCLEAN_SPHINCSSHA256128SROBUST_CLEAN_ull_to_bytes(out, 1, addr[0]); /* drop 3 bytes of the layer field */
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PQCLEAN_SPHINCSSHA256128SROBUST_CLEAN_ull_to_bytes(out + 1, 4, addr[2]); /* drop the highest tree address word */
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PQCLEAN_SPHINCSSHA256128SROBUST_CLEAN_ull_to_bytes(out + 5, 4, addr[3]);
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PQCLEAN_SPHINCSSHA256128SROBUST_CLEAN_ull_to_bytes(out + 9, 1, addr[4]); /* drop 3 bytes of the type field */
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PQCLEAN_SPHINCSSHA256128SROBUST_CLEAN_ull_to_bytes(out + 10, 4, addr[5]);
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PQCLEAN_SPHINCSSHA256128SROBUST_CLEAN_ull_to_bytes(out + 14, 4, addr[6]);
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PQCLEAN_SPHINCSSHA256128SROBUST_CLEAN_ull_to_bytes(out + 18, 4, addr[7]);
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}
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/**
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* Requires 'input_plus_four_bytes' to have 'inlen' + 4 bytes, so that the last
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* four bytes can be used for the counter. Typically 'input' is merely a seed.
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* Outputs outlen number of bytes
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*/
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void PQCLEAN_SPHINCSSHA256128SROBUST_CLEAN_mgf1(
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unsigned char *out, unsigned long outlen,
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unsigned char *input_plus_four_bytes, unsigned long inlen) {
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unsigned char outbuf[SPX_SHA256_OUTPUT_BYTES];
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unsigned long i;
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/* While we can fit in at least another full block of SHA256 output.. */
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for (i = 0; (i + 1)*SPX_SHA256_OUTPUT_BYTES <= outlen; i++) {
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PQCLEAN_SPHINCSSHA256128SROBUST_CLEAN_ull_to_bytes(input_plus_four_bytes + inlen, 4, i);
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sha256(out, input_plus_four_bytes, inlen + 4);
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out += SPX_SHA256_OUTPUT_BYTES;
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}
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/* Until we cannot anymore, and we fill the remainder. */
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if (outlen > i * SPX_SHA256_OUTPUT_BYTES) {
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PQCLEAN_SPHINCSSHA256128SROBUST_CLEAN_ull_to_bytes(input_plus_four_bytes + inlen, 4, i);
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sha256(outbuf, input_plus_four_bytes, inlen + 4);
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memcpy(out, outbuf, outlen - i * SPX_SHA256_OUTPUT_BYTES);
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}
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}
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/**
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* Absorb the constant pub_seed using one round of the compression function
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* This initializes hash_state_seeded, which can then be reused in thash
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**/
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void PQCLEAN_SPHINCSSHA256128SROBUST_CLEAN_seed_state(sha256ctx *hash_state_seeded, const unsigned char *pub_seed) {
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uint8_t block[SPX_SHA256_BLOCK_BYTES];
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size_t i;
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for (i = 0; i < SPX_N; ++i) {
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block[i] = pub_seed[i];
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}
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for (i = SPX_N; i < SPX_SHA256_BLOCK_BYTES; ++i) {
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block[i] = 0;
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}
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sha256_inc_init(hash_state_seeded);
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sha256_inc_blocks(hash_state_seeded, block, 1);
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}
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