76 lines
2.9 KiB
C
76 lines
2.9 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_SPHINCSSHA256256FROBUST_CLEAN_compress_address(unsigned char *out, const uint32_t addr[8]) {
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PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(out, 1, addr[0]); /* drop 3 bytes of the layer field */
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PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(out + 1, 4, addr[2]); /* drop the highest tree address word */
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PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(out + 5, 4, addr[3]);
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PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(out + 9, 1, addr[4]); /* drop 3 bytes of the type field */
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PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(out + 10, 4, addr[5]);
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PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(out + 14, 4, addr[6]);
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PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(out + 18, 4, addr[7]);
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}
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/**
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* Note that inlen should be sufficiently small that it still allows for
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* an array to be allocated on the stack. Typically 'in' is merely a seed.
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* Outputs outlen number of bytes
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*/
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void PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_mgf1(
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unsigned char *out, unsigned long outlen,
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const unsigned char *in, unsigned long inlen) {
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unsigned char inbuf[inlen + 4];
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unsigned char outbuf[SPX_SHA256_OUTPUT_BYTES];
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unsigned long i;
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memcpy(inbuf, in, inlen);
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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_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(inbuf + inlen, 4, i);
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sha256(out, inbuf, 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_SPHINCSSHA256256FROBUST_CLEAN_ull_to_bytes(inbuf + inlen, 4, i);
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sha256(outbuf, inbuf, 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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uint8_t PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_state_seeded[40];
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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 state_seeded, which can then be reused in thash
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**/
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void PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_seed_state(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(PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_state_seeded);
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sha256_inc_blocks(PQCLEAN_SPHINCSSHA256256FROBUST_CLEAN_state_seeded, block, 1);
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}
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