mbedtls/tinycrypt/ecc_dh.c
2019-11-26 12:52:57 +01:00

183 lines
6.5 KiB
C

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