versions/v1_4_0/mynewt-core/crypto/tinycrypt/src/ecc_dh.c - mynewt-documentation - Git at Google

 /* ec_dh.c - TinyCrypt implementation of EC-DH */

 /*
  * 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.
  */
 #include <tinycrypt/constants.h>
 #include <tinycrypt/ecc.h>
 #include <tinycrypt/ecc_dh.h>
 #include <string.h>

 #if default_RNG_defined
 static uECC_RNG_Function g_rng_function = &default_CSPRNG;
 #else
 static uECC_RNG_Function g_rng_function = 0;
 #endif

 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. */
 	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(curve->num_n_bits),
 				       _private);
 		uECC_vli_nativeToBytes(public_key,
 				       curve->num_bytes,
 				       _public);
 		uECC_vli_nativeToBytes(public_key + curve->num_bytes,
 				       curve->num_bytes,
 				       _public + curve->num_words);

 		/* erasing temporary buffer used to store secret: */
 		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, BITS_TO_WORDS(curve->num_n_bits));

 		/* 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(curve->num_n_bits),
 					       _private);
 			uECC_vli_nativeToBytes(public_key,
 					       curve->num_bytes,
 					       _public);
 			uECC_vli_nativeToBytes(public_key + curve->num_bytes,
  					       curve->num_bytes,
 					       _public + curve->num_words);

 			/* erasing temporary buffer that stored secret: */
 			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];

 	uECC_word_t tmp[NUM_ECC_WORDS];
 	uECC_word_t *p2[2] = {_private, tmp};
 	uECC_word_t *initial_Z = 0;
 	uECC_word_t carry;
 	wordcount_t num_words = curve->num_words;
 	wordcount_t num_bytes = curve->num_bytes;
 	int r;

 	/* Converting buffers to correct bit order: */
 	uECC_vli_bytesToNative(_private,
       			       private_key,
 			       BITS_TO_BYTES(curve->num_n_bits));
 	uECC_vli_bytesToNative(_public,
       			       public_key,
 			       num_bytes);
 	uECC_vli_bytesToNative(_public + num_words,
 			       public_key + num_bytes,
 			       num_bytes);

 	/* Regularize the bitcount for the private key so that attackers cannot use a
 	 * side channel attack to learn the number of leading zeros. */
 	carry = regularize_k(_private, _private, tmp, curve);

 	/* If an RNG function was specified, try to get a random initial Z value to
 	 * improve protection against side-channel attacks. */
 	if (g_rng_function) {
 		if (!uECC_generate_random_int(p2[carry], curve->p, num_words)) {
 			r = 0;
 			goto clear_and_out;
     		}
     		initial_Z = p2[carry];
   	}

 	EccPoint_mult(_public, _public, p2[!carry], initial_Z, curve->num_n_bits + 1,
 		      curve);

 	uECC_vli_nativeToBytes(secret, num_bytes, _public);
 	r = !EccPoint_isZero(_public, curve);

 clear_and_out:
 	/* erasing temporary buffer used to store secret: */
 	memset(p2, 0, sizeof(p2));
 	__asm__ __volatile__("" :: "g"(p2) : "memory");
 	memset(tmp, 0, sizeof(tmp));
 	__asm__ __volatile__("" :: "g"(tmp) : "memory");
 	memset(_private, 0, sizeof(_private));
 	__asm__ __volatile__("" :: "g"(_private) : "memory");

 	return r;
 }
	/* ec_dh.c - TinyCrypt implementation of EC-DH */

	/*
	* 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.
	*/
	#include <tinycrypt/constants.h>
	#include <tinycrypt/ecc.h>
	#include <tinycrypt/ecc_dh.h>
	#include <string.h>

	#if default_RNG_defined
	static uECC_RNG_Function g_rng_function = &default_CSPRNG;
	#else
	static uECC_RNG_Function g_rng_function = 0;
	#endif

	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. */
	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(curve->num_n_bits),
	_private);
	uECC_vli_nativeToBytes(public_key,
	curve->num_bytes,
	_public);
	uECC_vli_nativeToBytes(public_key + curve->num_bytes,
	curve->num_bytes,
	_public + curve->num_words);

	/* erasing temporary buffer used to store secret: */
	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, BITS_TO_WORDS(curve->num_n_bits));

	/* 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(curve->num_n_bits),
	_private);
	uECC_vli_nativeToBytes(public_key,
	curve->num_bytes,
	_public);
	uECC_vli_nativeToBytes(public_key + curve->num_bytes,
	curve->num_bytes,
	_public + curve->num_words);

	/* erasing temporary buffer that stored secret: */
	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];

	uECC_word_t tmp[NUM_ECC_WORDS];
	uECC_word_t *p2[2] = {_private, tmp};
	uECC_word_t *initial_Z = 0;
	uECC_word_t carry;
	wordcount_t num_words = curve->num_words;
	wordcount_t num_bytes = curve->num_bytes;
	int r;

	/* Converting buffers to correct bit order: */
	uECC_vli_bytesToNative(_private,
	private_key,
	BITS_TO_BYTES(curve->num_n_bits));
	uECC_vli_bytesToNative(_public,
	public_key,
	num_bytes);
	uECC_vli_bytesToNative(_public + num_words,
	public_key + num_bytes,
	num_bytes);

	/* Regularize the bitcount for the private key so that attackers cannot use a
	* side channel attack to learn the number of leading zeros. */
	carry = regularize_k(_private, _private, tmp, curve);

	/* If an RNG function was specified, try to get a random initial Z value to
	* improve protection against side-channel attacks. */
	if (g_rng_function) {
	if (!uECC_generate_random_int(p2[carry], curve->p, num_words)) {
	r = 0;
	goto clear_and_out;
	}
	initial_Z = p2[carry];
	}

	EccPoint_mult(_public, _public, p2[!carry], initial_Z, curve->num_n_bits + 1,
	curve);

	uECC_vli_nativeToBytes(secret, num_bytes, _public);
	r = !EccPoint_isZero(_public, curve);

	clear_and_out:
	/* erasing temporary buffer used to store secret: */
	memset(p2, 0, sizeof(p2));
	__asm__ __volatile__("" :: "g"(p2) : "memory");
	memset(tmp, 0, sizeof(tmp));
	__asm__ __volatile__("" :: "g"(tmp) : "memory");
	memset(_private, 0, sizeof(_private));
	__asm__ __volatile__("" :: "g"(_private) : "memory");

	return r;
	}