mirror of
https://github.com/henrydcase/pqc.git
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88 lines
3.0 KiB
C
88 lines
3.0 KiB
C
#include <stdint.h>
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#include <string.h>
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#include "address.h"
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#include "hash.h"
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#include "params.h"
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#include "utils.h"
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#include "fips202.h"
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/* For SHAKE256, there is no immediate reason to initialize at the start,
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so this function is an empty operation. */
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void PQCLEAN_SPHINCSSHAKE256256SSIMPLE_CLEAN_initialize_hash_function(
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const unsigned char *pub_seed, const unsigned char *sk_seed) {
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(void)pub_seed; /* Suppress an 'unused parameter' warning. */
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(void)sk_seed; /* Suppress an 'unused parameter' warning. */
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}
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/*
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* Computes PRF(key, addr), given a secret key of SPX_N bytes and an address
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*/
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void PQCLEAN_SPHINCSSHAKE256256SSIMPLE_CLEAN_prf_addr(
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unsigned char *out, const unsigned char *key, const uint32_t addr[8]) {
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unsigned char buf[SPX_N + SPX_ADDR_BYTES];
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memcpy(buf, key, SPX_N);
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PQCLEAN_SPHINCSSHAKE256256SSIMPLE_CLEAN_addr_to_bytes(buf + SPX_N, addr);
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shake256(out, SPX_N, buf, SPX_N + SPX_ADDR_BYTES);
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}
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/**
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* Computes the message-dependent randomness R, using a secret seed and an
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* optional randomization value as well as the message.
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*/
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void PQCLEAN_SPHINCSSHAKE256256SSIMPLE_CLEAN_gen_message_random(
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unsigned char *R,
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const unsigned char *sk_prf, const unsigned char *optrand,
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const unsigned char *m, size_t mlen) {
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shake256incctx state;
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shake256_inc_init(&state);
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shake256_inc_absorb(&state, sk_prf, SPX_N);
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shake256_inc_absorb(&state, optrand, SPX_N);
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shake256_inc_absorb(&state, m, mlen);
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shake256_inc_finalize(&state);
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shake256_inc_squeeze(R, SPX_N, &state);
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}
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/**
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* Computes the message hash using R, the public key, and the message.
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* Outputs the message digest and the index of the leaf. The index is split in
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* the tree index and the leaf index, for convenient copying to an address.
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*/
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void PQCLEAN_SPHINCSSHAKE256256SSIMPLE_CLEAN_hash_message(
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unsigned char *digest, uint64_t *tree, uint32_t *leaf_idx,
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const unsigned char *R, const unsigned char *pk,
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const unsigned char *m, size_t mlen) {
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#define SPX_TREE_BITS (SPX_TREE_HEIGHT * (SPX_D - 1))
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#define SPX_TREE_BYTES ((SPX_TREE_BITS + 7) / 8)
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#define SPX_LEAF_BITS SPX_TREE_HEIGHT
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#define SPX_LEAF_BYTES ((SPX_LEAF_BITS + 7) / 8)
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#define SPX_DGST_BYTES (SPX_FORS_MSG_BYTES + SPX_TREE_BYTES + SPX_LEAF_BYTES)
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unsigned char buf[SPX_DGST_BYTES];
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unsigned char *bufp = buf;
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shake256incctx state;
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shake256_inc_init(&state);
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shake256_inc_absorb(&state, R, SPX_N);
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shake256_inc_absorb(&state, pk, SPX_PK_BYTES);
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shake256_inc_absorb(&state, m, mlen);
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shake256_inc_finalize(&state);
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shake256_inc_squeeze(buf, SPX_DGST_BYTES, &state);
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memcpy(digest, bufp, SPX_FORS_MSG_BYTES);
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bufp += SPX_FORS_MSG_BYTES;
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*tree = PQCLEAN_SPHINCSSHAKE256256SSIMPLE_CLEAN_bytes_to_ull(
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bufp, SPX_TREE_BYTES);
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*tree &= (~(uint64_t)0) >> (64 - SPX_TREE_BITS);
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bufp += SPX_TREE_BYTES;
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*leaf_idx = (uint32_t)PQCLEAN_SPHINCSSHAKE256256SSIMPLE_CLEAN_bytes_to_ull(
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bufp, SPX_LEAF_BYTES);
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*leaf_idx &= (~(uint32_t)0) >> (32 - SPX_LEAF_BITS);
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}
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