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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 | /* 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; } |