1 /* Copyright (c) 2018, Google Inc. 2 * 3 * Permission to use, copy, modify, and/or distribute this software for any 4 * purpose with or without fee is hereby granted, provided that the above 5 * copyright notice and this permission notice appear in all copies. 6 * 7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 10 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION 12 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN 13 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ 14 15 #include <openssl/ec.h> 16 #include <openssl/err.h> 17 #include <openssl/mem.h> 18 19 #include "internal.h" 20 #include "../bn/internal.h" 21 #include "../../internal.h" 22 23 24 int ec_bignum_to_scalar(const EC_GROUP *group, EC_SCALAR *out, 25 const BIGNUM *in) { 26 if (!bn_copy_words(out->words, group->order.width, in) || 27 !bn_less_than_words(out->words, group->order.d, group->order.width)) { 28 OPENSSL_PUT_ERROR(EC, EC_R_INVALID_SCALAR); 29 return 0; 30 } 31 return 1; 32 } 33 34 int ec_scalar_equal_vartime(const EC_GROUP *group, const EC_SCALAR *a, 35 const EC_SCALAR *b) { 36 return OPENSSL_memcmp(a->words, b->words, 37 group->order.width * sizeof(BN_ULONG)) == 0; 38 } 39 40 int ec_scalar_is_zero(const EC_GROUP *group, const EC_SCALAR *a) { 41 BN_ULONG mask = 0; 42 for (int i = 0; i < group->order.width; i++) { 43 mask |= a->words[i]; 44 } 45 return mask == 0; 46 } 47 48 int ec_random_nonzero_scalar(const EC_GROUP *group, EC_SCALAR *out, 49 const uint8_t additional_data[32]) { 50 return bn_rand_range_words(out->words, 1, group->order.d, group->order.width, 51 additional_data); 52 } 53 54 void ec_scalar_add(const EC_GROUP *group, EC_SCALAR *r, const EC_SCALAR *a, 55 const EC_SCALAR *b) { 56 const BIGNUM *order = &group->order; 57 BN_ULONG tmp[EC_MAX_WORDS]; 58 bn_mod_add_words(r->words, a->words, b->words, order->d, tmp, order->width); 59 OPENSSL_cleanse(tmp, sizeof(tmp)); 60 } 61 62 void ec_scalar_to_montgomery(const EC_GROUP *group, EC_SCALAR *r, 63 const EC_SCALAR *a) { 64 const BIGNUM *order = &group->order; 65 bn_to_montgomery_small(r->words, a->words, order->width, group->order_mont); 66 } 67 68 void ec_scalar_from_montgomery(const EC_GROUP *group, EC_SCALAR *r, 69 const EC_SCALAR *a) { 70 const BIGNUM *order = &group->order; 71 bn_from_montgomery_small(r->words, a->words, order->width, group->order_mont); 72 } 73 74 void ec_scalar_mul_montgomery(const EC_GROUP *group, EC_SCALAR *r, 75 const EC_SCALAR *a, const EC_SCALAR *b) { 76 const BIGNUM *order = &group->order; 77 bn_mod_mul_montgomery_small(r->words, a->words, b->words, order->width, 78 group->order_mont); 79 } 80 81 void ec_simple_scalar_inv_montgomery(const EC_GROUP *group, EC_SCALAR *r, 82 const EC_SCALAR *a) { 83 const BIGNUM *order = &group->order; 84 bn_mod_inverse_prime_mont_small(r->words, a->words, order->width, 85 group->order_mont); 86 } 87 88 void ec_scalar_inv_montgomery(const EC_GROUP *group, EC_SCALAR *r, 89 const EC_SCALAR *a) { 90 group->meth->scalar_inv_montgomery(group, r, a); 91 } 92 93 int ec_scalar_inv_montgomery_vartime(const EC_GROUP *group, EC_SCALAR *r, 94 const EC_SCALAR *a) { 95 return group->meth->scalar_inv_montgomery_vartime(group, r, a); 96 } 97
