mirror of
https://github.com/trezor/trezor-firmware.git
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63 lines
2.3 KiB
C
63 lines
2.3 KiB
C
/**
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* Copyright (c) 2013-2014 Tomas Dzetkulic
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* Copyright (c) 2013-2014 Pavol Rusnak
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* Copyright (c) 2015 Jochen Hoenicke
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES
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* OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*/
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#include <assert.h>
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#include "hmac_drbg.h"
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#include "memzero.h"
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#include "rfc6979.h"
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void init_rfc6979(const uint8_t *priv_key, const uint8_t *hash,
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const ecdsa_curve *curve, rfc6979_state *state) {
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if (curve) {
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bignum256 hash_bn = {0};
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bn_read_be(hash, &hash_bn);
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// Make sure hash is partly reduced modulo order
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assert(bn_bitcount(&curve->order) >= 256);
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bn_mod(&hash_bn, &curve->order);
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uint8_t hash_reduced[32] = {0};
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bn_write_be(&hash_bn, hash_reduced);
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memzero(&hash_bn, sizeof(hash_bn));
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hmac_drbg_init(state, priv_key, 32, hash_reduced, 32);
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memzero(hash_reduced, sizeof(hash_reduced));
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} else {
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hmac_drbg_init(state, priv_key, 32, hash, 32);
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}
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}
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// generate next number from deterministic random number generator
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void generate_rfc6979(uint8_t rnd[32], rfc6979_state *state) {
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hmac_drbg_generate(state, rnd, 32);
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}
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// generate K in a deterministic way, according to RFC6979
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// http://tools.ietf.org/html/rfc6979
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void generate_k_rfc6979(bignum256 *k, rfc6979_state *state) {
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uint8_t buf[32] = {0};
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generate_rfc6979(buf, state);
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bn_read_be(buf, k);
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memzero(buf, sizeof(buf));
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}
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