diff options
Diffstat (limited to 'src/crypto/spx/spx.c')
-rw-r--r-- | src/crypto/spx/spx.c | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/src/crypto/spx/spx.c b/src/crypto/spx/spx.c new file mode 100644 index 00000000..679a4a1c --- /dev/null +++ b/src/crypto/spx/spx.c @@ -0,0 +1,139 @@ +/* Copyright (c) 2023, Google LLC + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY + * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION + * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN + * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ + +#include <openssl/base.h> + +#include <string.h> + +#include <openssl/rand.h> + +#include "./address.h" +#include "./fors.h" +#include "./internal.h" +#include "./merkle.h" +#include "./params.h" +#include "./spx_util.h" +#include "./thash.h" + +void spx_generate_key(uint8_t out_public_key[SPX_PUBLIC_KEY_BYTES], + uint8_t out_secret_key[SPX_SECRET_KEY_BYTES]) { + uint8_t seed[3 * SPX_N]; + RAND_bytes(seed, 3 * SPX_N); + spx_generate_key_from_seed(out_public_key, out_secret_key, seed); +} + +void spx_generate_key_from_seed(uint8_t out_public_key[SPX_PUBLIC_KEY_BYTES], + uint8_t out_secret_key[SPX_SECRET_KEY_BYTES], + const uint8_t seed[3 * SPX_N]) { + // Initialize SK.seed || SK.prf || PK.seed from seed. + memcpy(out_secret_key, seed, 3 * SPX_N); + + // Initialize PK.seed from seed. + memcpy(out_public_key, seed + 2 * SPX_N, SPX_N); + + uint8_t addr[32] = {0}; + spx_set_layer_addr(addr, SPX_D - 1); + + // Set PK.root + spx_treehash(out_public_key + SPX_N, out_secret_key, 0, SPX_TREE_HEIGHT, + out_public_key, addr); + memcpy(out_secret_key + 3 * SPX_N, out_public_key + SPX_N, SPX_N); +} + +void spx_sign(uint8_t out_signature[SPX_SIGNATURE_BYTES], + const uint8_t secret_key[SPX_SECRET_KEY_BYTES], + const uint8_t *msg, size_t msg_len, int randomized) { + uint8_t addr[32] = {0}; + const uint8_t *sk_seed = secret_key; + const uint8_t *sk_prf = secret_key + SPX_N; + const uint8_t *pk_seed = secret_key + 2 * SPX_N; + const uint8_t *pk_root = secret_key + 3 * SPX_N; + + uint8_t opt_rand[SPX_N] = {0}; + + if (randomized) { + RAND_bytes(opt_rand, SPX_N); + } else { + memcpy(opt_rand, pk_seed, SPX_N); + } + + // Derive randomizer r and copy it to signature. + uint8_t r[SPX_N]; + spx_thash_prfmsg(r, sk_prf, opt_rand, msg, msg_len); + memcpy(out_signature, r, SPX_N); + + uint8_t digest[SPX_DIGEST_SIZE]; + spx_thash_hmsg(digest, r, pk_seed, pk_root, msg, msg_len); + + uint8_t fors_digest[SPX_FORS_MSG_BYTES]; + memcpy(fors_digest, digest, SPX_FORS_MSG_BYTES); + + uint8_t *tmp_idx_tree = digest + SPX_FORS_MSG_BYTES; + uint8_t *tmp_idx_leaf = tmp_idx_tree + SPX_TREE_BYTES; + + uint64_t idx_tree = spx_to_uint64(tmp_idx_tree, SPX_TREE_BYTES); + idx_tree &= (~(uint64_t)0) >> (64 - SPX_TREE_BITS); + + uint32_t idx_leaf = (uint32_t)spx_to_uint64(tmp_idx_leaf, SPX_LEAF_BYTES); + idx_leaf &= (~(uint32_t)0) >> (32 - SPX_LEAF_BITS); + + spx_set_tree_addr(addr, idx_tree); + spx_set_type(addr, SPX_ADDR_TYPE_FORSTREE); + spx_set_keypair_addr(addr, idx_leaf); + + spx_fors_sign(out_signature + SPX_N, fors_digest, sk_seed, pk_seed, addr); + + uint8_t pk_fors[SPX_N]; + spx_fors_pk_from_sig(pk_fors, out_signature + SPX_N, fors_digest, pk_seed, + addr); + + spx_ht_sign(out_signature + SPX_N + SPX_FORS_BYTES, pk_fors, idx_tree, + idx_leaf, sk_seed, pk_seed); +} + +int spx_verify(const uint8_t signature[SPX_SIGNATURE_BYTES], + const uint8_t public_key[SPX_SECRET_KEY_BYTES], + const uint8_t *msg, size_t msg_len) { + uint8_t addr[32] = {0}; + const uint8_t *pk_seed = public_key; + const uint8_t *pk_root = public_key + SPX_N; + + const uint8_t *r = signature; + const uint8_t *sig_fors = signature + SPX_N; + const uint8_t *sig_ht = sig_fors + SPX_FORS_BYTES; + + uint8_t digest[SPX_DIGEST_SIZE]; + spx_thash_hmsg(digest, r, pk_seed, pk_root, msg, msg_len); + + uint8_t fors_digest[SPX_FORS_MSG_BYTES]; + memcpy(fors_digest, digest, SPX_FORS_MSG_BYTES); + + uint8_t *tmp_idx_tree = digest + SPX_FORS_MSG_BYTES; + uint8_t *tmp_idx_leaf = tmp_idx_tree + SPX_TREE_BYTES; + + uint64_t idx_tree = spx_to_uint64(tmp_idx_tree, SPX_TREE_BYTES); + idx_tree &= (~(uint64_t)0) >> (64 - SPX_TREE_BITS); + + uint32_t idx_leaf = (uint32_t)spx_to_uint64(tmp_idx_leaf, SPX_LEAF_BYTES); + idx_leaf &= (~(uint32_t)0) >> (32 - SPX_LEAF_BITS); + + spx_set_tree_addr(addr, idx_tree); + spx_set_type(addr, SPX_ADDR_TYPE_FORSTREE); + spx_set_keypair_addr(addr, idx_leaf); + + uint8_t pk_fors[SPX_N]; + spx_fors_pk_from_sig(pk_fors, sig_fors, fors_digest, pk_seed, addr); + + return spx_ht_verify(sig_ht, pk_fors, idx_tree, idx_leaf, pk_root, pk_seed); +} |