mirror of
https://github.com/trezor/trezor-firmware.git
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63 lines
2.2 KiB
C
63 lines
2.2 KiB
C
/*
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* This file is part of the Trezor project, https://trezor.io/
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*
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* Copyright (c) SatoshiLabs
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "chacha_drbg.h"
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#include <stdint.h>
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#define MAX(a, b) (a) > (b) ? (a) : (b)
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void chacha_drbg_init(CHACHA_DRBG_CTX *ctx,
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const uint8_t entropy[CHACHA_DRBG_SEED_LENGTH]) {
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uint8_t buffer[MAX(CHACHA_DRBG_KEY_LENGTH, CHACHA_DRBG_IV_LENGTH)] = {0};
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ECRYPT_keysetup(&ctx->chacha_ctx, buffer, CHACHA_DRBG_KEY_LENGTH * 8,
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CHACHA_DRBG_IV_LENGTH * 8);
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ECRYPT_ivsetup(&ctx->chacha_ctx, buffer);
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chacha_drbg_reseed(ctx, entropy);
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}
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static void chacha_drbg_update(CHACHA_DRBG_CTX *ctx,
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const uint8_t data[CHACHA_DRBG_SEED_LENGTH]) {
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uint8_t buffer[CHACHA_DRBG_SEED_LENGTH] = {0};
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if (data)
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ECRYPT_encrypt_bytes(&ctx->chacha_ctx, data, buffer,
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CHACHA_DRBG_SEED_LENGTH);
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else
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ECRYPT_keystream_bytes(&ctx->chacha_ctx, buffer, CHACHA_DRBG_SEED_LENGTH);
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ECRYPT_keysetup(&ctx->chacha_ctx, buffer, CHACHA_DRBG_KEY_LENGTH * 8,
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CHACHA_DRBG_IV_LENGTH * 8);
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ECRYPT_ivsetup(&ctx->chacha_ctx, buffer + CHACHA_DRBG_KEY_LENGTH);
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}
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void chacha_drbg_generate(CHACHA_DRBG_CTX *ctx, uint8_t *output,
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uint8_t output_length) {
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ECRYPT_keystream_bytes(&ctx->chacha_ctx, output, output_length);
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chacha_drbg_update(ctx, NULL);
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ctx->reseed_counter++;
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}
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void chacha_drbg_reseed(CHACHA_DRBG_CTX *ctx,
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const uint8_t entropy[CHACHA_DRBG_SEED_LENGTH]) {
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chacha_drbg_update(ctx, entropy);
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ctx->reseed_counter = 1;
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}
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