/* Copyright (c) 2018, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include <openssl/ec.h>
#include <openssl/err.h>
#include <openssl/mem.h>
#include "internal.h"
#include "../bn/internal.h"
#include "../../internal.h"
int ec_bignum_to_scalar(const EC_GROUP *group, EC_SCALAR *out,
const BIGNUM *in) {
if (!bn_copy_words(out->words, group->order.width, in) ||
!bn_less_than_words(out->words, group->order.d, group->order.width)) {
OPENSSL_PUT_ERROR(EC, EC_R_INVALID_SCALAR);
return 0;
}
return 1;
}
int ec_scalar_equal_vartime(const EC_GROUP *group, const EC_SCALAR *a,
const EC_SCALAR *b) {
return OPENSSL_memcmp(a->words, b->words,
group->order.width * sizeof(BN_ULONG)) == 0;
}
int ec_scalar_is_zero(const EC_GROUP *group, const EC_SCALAR *a) {
BN_ULONG mask = 0;
for (int i = 0; i < group->order.width; i++) {
mask |= a->words[i];
}
return mask == 0;
}
int ec_random_nonzero_scalar(const EC_GROUP *group, EC_SCALAR *out,
const uint8_t additional_data[32]) {
return bn_rand_range_words(out->words, 1, group->order.d, group->order.width,
additional_data);
}
void ec_scalar_add(const EC_GROUP *group, EC_SCALAR *r, const EC_SCALAR *a,
const EC_SCALAR *b) {
const BIGNUM *order = &group->order;
BN_ULONG tmp[EC_MAX_WORDS];
bn_mod_add_words(r->words, a->words, b->words, order->d, tmp, order->width);
OPENSSL_cleanse(tmp, sizeof(tmp));
}
void ec_scalar_to_montgomery(const EC_GROUP *group, EC_SCALAR *r,
const EC_SCALAR *a) {
const BIGNUM *order = &group->order;
bn_to_montgomery_small(r->words, a->words, order->width, group->order_mont);
}
void ec_scalar_from_montgomery(const EC_GROUP *group, EC_SCALAR *r,
const EC_SCALAR *a) {
const BIGNUM *order = &group->order;
bn_from_montgomery_small(r->words, a->words, order->width, group->order_mont);
}
void ec_scalar_mul_montgomery(const EC_GROUP *group, EC_SCALAR *r,
const EC_SCALAR *a, const EC_SCALAR *b) {
const BIGNUM *order = &group->order;
bn_mod_mul_montgomery_small(r->words, a->words, b->words, order->width,
group->order_mont);
}
void ec_simple_scalar_inv_montgomery(const EC_GROUP *group, EC_SCALAR *r,
const EC_SCALAR *a) {
const BIGNUM *order = &group->order;
bn_mod_inverse_prime_mont_small(r->words, a->words, order->width,
group->order_mont);
}
void ec_scalar_inv_montgomery(const EC_GROUP *group, EC_SCALAR *r,
const EC_SCALAR *a) {
group->meth->scalar_inv_montgomery(group, r, a);
}
int ec_scalar_inv_montgomery_vartime(const EC_GROUP *group, EC_SCALAR *r,
const EC_SCALAR *a) {
return group->meth->scalar_inv_montgomery_vartime(group, r, a);
}