mirror of
https://github.com/yuzu-emu/mbedtls.git
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ef238283d5
This avoids the need for each calling site to manually regularize the scalar and randomize coordinates, which makes for simpler safe use and saves 50 bytes of code size in the library.
194 lines
6.8 KiB
C
194 lines
6.8 KiB
C
/* ec_dh.c - TinyCrypt implementation of EC-DH */
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/*
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* Copyright (c) 2019, Arm Limited (or its affiliates), All Rights Reserved.
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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/*
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* Copyright (c) 2014, Kenneth MacKay
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* * Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Copyright (C) 2017 by Intel Corporation, All Rights Reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* - Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* - Neither the name of Intel Corporation nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#if !defined(MBEDTLS_CONFIG_FILE)
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#include "mbedtls/config.h"
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#else
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#include MBEDTLS_CONFIG_FILE
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#endif
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#if defined(MBEDTLS_USE_TINYCRYPT)
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#include <tinycrypt/ecc.h>
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#include <tinycrypt/ecc_dh.h>
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#include <string.h>
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#include "mbedtls/platform_util.h"
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int uECC_make_key_with_d(uint8_t *public_key, uint8_t *private_key,
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unsigned int *d, uECC_Curve curve)
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{
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uECC_word_t _private[NUM_ECC_WORDS];
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uECC_word_t _public[NUM_ECC_WORDS * 2];
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/* This function is designed for test purposes-only (such as validating NIST
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* test vectors) as it uses a provided value for d instead of generating
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* it uniformly at random. */
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memcpy (_private, d, NUM_ECC_BYTES);
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/* Computing public-key from private: */
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if (EccPoint_compute_public_key(_public, _private, curve)) {
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/* Converting buffers to correct bit order: */
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uECC_vli_nativeToBytes(private_key,
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BITS_TO_BYTES(curve->num_n_bits),
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_private);
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uECC_vli_nativeToBytes(public_key,
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curve->num_bytes,
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_public);
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uECC_vli_nativeToBytes(public_key + curve->num_bytes,
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curve->num_bytes,
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_public + curve->num_words);
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/* erasing temporary buffer used to store secret: */
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mbedtls_platform_memset(_private, 0, NUM_ECC_BYTES);
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return 1;
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}
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return 0;
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}
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int uECC_make_key(uint8_t *public_key, uint8_t *private_key, uECC_Curve curve)
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{
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uECC_word_t _random[NUM_ECC_WORDS * 2];
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uECC_word_t _private[NUM_ECC_WORDS];
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uECC_word_t _public[NUM_ECC_WORDS * 2];
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uECC_word_t tries;
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for (tries = 0; tries < uECC_RNG_MAX_TRIES; ++tries) {
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/* Generating _private uniformly at random: */
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uECC_RNG_Function rng_function = uECC_get_rng();
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if (!rng_function ||
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!rng_function((uint8_t *)_random, 2 * NUM_ECC_WORDS*uECC_WORD_SIZE)) {
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return 0;
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}
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/* computing modular reduction of _random (see FIPS 186.4 B.4.1): */
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uECC_vli_mmod(_private, _random, curve->n, BITS_TO_WORDS(curve->num_n_bits));
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/* Computing public-key from private: */
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if (EccPoint_compute_public_key(_public, _private, curve)) {
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/* Converting buffers to correct bit order: */
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uECC_vli_nativeToBytes(private_key,
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BITS_TO_BYTES(curve->num_n_bits),
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_private);
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uECC_vli_nativeToBytes(public_key,
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curve->num_bytes,
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_public);
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uECC_vli_nativeToBytes(public_key + curve->num_bytes,
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curve->num_bytes,
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_public + curve->num_words);
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/* erasing temporary buffer that stored secret: */
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mbedtls_platform_memset(_private, 0, NUM_ECC_BYTES);
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return 1;
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}
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}
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return 0;
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}
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int uECC_shared_secret(const uint8_t *public_key, const uint8_t *private_key,
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uint8_t *secret, uECC_Curve curve)
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{
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uECC_word_t _public[NUM_ECC_WORDS * 2];
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uECC_word_t _private[NUM_ECC_WORDS];
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wordcount_t num_words = curve->num_words;
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wordcount_t num_bytes = curve->num_bytes;
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int r;
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/* Protect against invalid curve attacks */
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if (uECC_valid_public_key(public_key, curve) != 0) {
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r = 0;
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goto clear_and_out;
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}
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/* Converting buffers to correct bit order: */
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uECC_vli_bytesToNative(_private,
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private_key,
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BITS_TO_BYTES(curve->num_n_bits));
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uECC_vli_bytesToNative(_public,
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public_key,
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num_bytes);
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uECC_vli_bytesToNative(_public + num_words,
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public_key + num_bytes,
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num_bytes);
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r = EccPoint_mult_safer(_public, _public, _private, curve);
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if (r == 0)
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goto clear_and_out;
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uECC_vli_nativeToBytes(secret, num_bytes, _public);
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r = !EccPoint_isZero(_public, curve);
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clear_and_out:
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/* erasing temporary buffer used to store secret: */
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mbedtls_platform_zeroize(_private, sizeof(_private));
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return r;
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}
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#else
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typedef int mbedtls_dummy_tinycrypt_def;
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#endif /* MBEDTLS_USE_TINYCRYPT */
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