mirror of
https://github.com/trezor/trezor-firmware.git
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78 lines
2.9 KiB
C
78 lines
2.9 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 "rfc6979.h"
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#include <string.h>
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#include "hmac.h"
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#include "memzero.h"
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void init_rfc6979(const uint8_t *priv_key, const uint8_t *hash,
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rfc6979_state *state) {
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uint8_t bx[2 * 32];
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uint8_t buf[32 + 1 + 2 * 32];
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memcpy(bx, priv_key, 32);
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memcpy(bx + 32, hash, 32);
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memset(state->v, 1, sizeof(state->v));
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memset(state->k, 0, sizeof(state->k));
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memcpy(buf, state->v, sizeof(state->v));
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buf[sizeof(state->v)] = 0x00;
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memcpy(buf + sizeof(state->v) + 1, bx, 64);
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hmac_sha256(state->k, sizeof(state->k), buf, sizeof(buf), state->k);
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hmac_sha256(state->k, sizeof(state->k), state->v, sizeof(state->v), state->v);
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memcpy(buf, state->v, sizeof(state->v));
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buf[sizeof(state->v)] = 0x01;
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memcpy(buf + sizeof(state->v) + 1, bx, 64);
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hmac_sha256(state->k, sizeof(state->k), buf, sizeof(buf), state->k);
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hmac_sha256(state->k, sizeof(state->k), state->v, sizeof(state->v), state->v);
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memzero(bx, sizeof(bx));
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memzero(buf, sizeof(buf));
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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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uint8_t buf[32 + 1];
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hmac_sha256(state->k, sizeof(state->k), state->v, sizeof(state->v), state->v);
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memcpy(buf, state->v, sizeof(state->v));
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buf[sizeof(state->v)] = 0x00;
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hmac_sha256(state->k, sizeof(state->k), buf, sizeof(state->v) + 1, state->k);
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hmac_sha256(state->k, sizeof(state->k), state->v, sizeof(state->v), state->v);
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memcpy(rnd, buf, 32);
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memzero(buf, sizeof(buf));
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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];
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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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