292 lines
7.8 KiB
C
292 lines
7.8 KiB
C
/*
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* Copyright 2001-2019 The OpenSSL Project Authors. All Rights Reserved.
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* Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
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*
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* Licensed under the OpenSSL license (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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#include <openssl/err.h>
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#include "ec_local.h"
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const EC_METHOD *EC_GFp_mont_method(void)
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{
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static const EC_METHOD ret = {
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EC_FLAGS_DEFAULT_OCT,
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NID_X9_62_prime_field,
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ec_GFp_mont_group_init,
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ec_GFp_mont_group_finish,
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ec_GFp_mont_group_clear_finish,
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ec_GFp_mont_group_copy,
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ec_GFp_mont_group_set_curve,
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ec_GFp_simple_group_get_curve,
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ec_GFp_simple_group_get_degree,
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ec_group_simple_order_bits,
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ec_GFp_simple_group_check_discriminant,
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ec_GFp_simple_point_init,
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ec_GFp_simple_point_finish,
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ec_GFp_simple_point_clear_finish,
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ec_GFp_simple_point_copy,
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ec_GFp_simple_point_set_to_infinity,
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ec_GFp_simple_set_Jprojective_coordinates_GFp,
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ec_GFp_simple_get_Jprojective_coordinates_GFp,
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ec_GFp_simple_point_set_affine_coordinates,
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ec_GFp_simple_point_get_affine_coordinates,
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0, 0, 0,
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ec_GFp_simple_add,
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ec_GFp_simple_dbl,
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ec_GFp_simple_invert,
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ec_GFp_simple_is_at_infinity,
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ec_GFp_simple_is_on_curve,
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ec_GFp_simple_cmp,
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ec_GFp_simple_make_affine,
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ec_GFp_simple_points_make_affine,
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0 /* mul */ ,
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0 /* precompute_mult */ ,
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0 /* have_precompute_mult */ ,
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ec_GFp_mont_field_mul,
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ec_GFp_mont_field_sqr,
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0 /* field_div */ ,
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ec_GFp_mont_field_inv,
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ec_GFp_mont_field_encode,
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ec_GFp_mont_field_decode,
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ec_GFp_mont_field_set_to_one,
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ec_key_simple_priv2oct,
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ec_key_simple_oct2priv,
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0, /* set private */
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ec_key_simple_generate_key,
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ec_key_simple_check_key,
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ec_key_simple_generate_public_key,
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0, /* keycopy */
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0, /* keyfinish */
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ecdh_simple_compute_key,
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0, /* field_inverse_mod_ord */
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ec_GFp_simple_blind_coordinates,
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ec_GFp_simple_ladder_pre,
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ec_GFp_simple_ladder_step,
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ec_GFp_simple_ladder_post
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};
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return &ret;
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}
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int ec_GFp_mont_group_init(EC_GROUP *group)
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{
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int ok;
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ok = ec_GFp_simple_group_init(group);
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group->field_data1 = NULL;
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group->field_data2 = NULL;
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return ok;
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}
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void ec_GFp_mont_group_finish(EC_GROUP *group)
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{
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BN_MONT_CTX_free(group->field_data1);
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group->field_data1 = NULL;
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BN_free(group->field_data2);
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group->field_data2 = NULL;
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ec_GFp_simple_group_finish(group);
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}
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void ec_GFp_mont_group_clear_finish(EC_GROUP *group)
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{
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BN_MONT_CTX_free(group->field_data1);
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group->field_data1 = NULL;
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BN_clear_free(group->field_data2);
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group->field_data2 = NULL;
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ec_GFp_simple_group_clear_finish(group);
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}
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int ec_GFp_mont_group_copy(EC_GROUP *dest, const EC_GROUP *src)
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{
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BN_MONT_CTX_free(dest->field_data1);
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dest->field_data1 = NULL;
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BN_clear_free(dest->field_data2);
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dest->field_data2 = NULL;
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if (!ec_GFp_simple_group_copy(dest, src))
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return 0;
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if (src->field_data1 != NULL) {
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dest->field_data1 = BN_MONT_CTX_new();
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if (dest->field_data1 == NULL)
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return 0;
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if (!BN_MONT_CTX_copy(dest->field_data1, src->field_data1))
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goto err;
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}
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if (src->field_data2 != NULL) {
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dest->field_data2 = BN_dup(src->field_data2);
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if (dest->field_data2 == NULL)
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goto err;
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}
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return 1;
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err:
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BN_MONT_CTX_free(dest->field_data1);
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dest->field_data1 = NULL;
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return 0;
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}
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int ec_GFp_mont_group_set_curve(EC_GROUP *group, const BIGNUM *p,
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const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
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{
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BN_CTX *new_ctx = NULL;
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BN_MONT_CTX *mont = NULL;
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BIGNUM *one = NULL;
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int ret = 0;
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BN_MONT_CTX_free(group->field_data1);
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group->field_data1 = NULL;
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BN_free(group->field_data2);
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group->field_data2 = NULL;
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if (ctx == NULL) {
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ctx = new_ctx = BN_CTX_new();
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if (ctx == NULL)
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return 0;
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}
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mont = BN_MONT_CTX_new();
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if (mont == NULL)
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goto err;
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if (!BN_MONT_CTX_set(mont, p, ctx)) {
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ECerr(EC_F_EC_GFP_MONT_GROUP_SET_CURVE, ERR_R_BN_LIB);
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goto err;
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}
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one = BN_new();
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if (one == NULL)
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goto err;
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if (!BN_to_montgomery(one, BN_value_one(), mont, ctx))
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goto err;
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group->field_data1 = mont;
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mont = NULL;
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group->field_data2 = one;
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one = NULL;
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ret = ec_GFp_simple_group_set_curve(group, p, a, b, ctx);
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if (!ret) {
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BN_MONT_CTX_free(group->field_data1);
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group->field_data1 = NULL;
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BN_free(group->field_data2);
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group->field_data2 = NULL;
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}
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err:
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BN_free(one);
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BN_CTX_free(new_ctx);
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BN_MONT_CTX_free(mont);
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return ret;
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}
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int ec_GFp_mont_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
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const BIGNUM *b, BN_CTX *ctx)
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{
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if (group->field_data1 == NULL) {
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ECerr(EC_F_EC_GFP_MONT_FIELD_MUL, EC_R_NOT_INITIALIZED);
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return 0;
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}
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return BN_mod_mul_montgomery(r, a, b, group->field_data1, ctx);
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}
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int ec_GFp_mont_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
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BN_CTX *ctx)
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{
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if (group->field_data1 == NULL) {
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ECerr(EC_F_EC_GFP_MONT_FIELD_SQR, EC_R_NOT_INITIALIZED);
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return 0;
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}
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return BN_mod_mul_montgomery(r, a, a, group->field_data1, ctx);
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}
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/*-
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* Computes the multiplicative inverse of a in GF(p), storing the result in r.
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* If a is zero (or equivalent), you'll get a EC_R_CANNOT_INVERT error.
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* We have a Mont structure, so SCA hardening is FLT inversion.
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*/
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int ec_GFp_mont_field_inv(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
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BN_CTX *ctx)
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{
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BIGNUM *e = NULL;
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BN_CTX *new_ctx = NULL;
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int ret = 0;
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if (group->field_data1 == NULL)
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return 0;
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if (ctx == NULL && (ctx = new_ctx = BN_CTX_secure_new()) == NULL)
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return 0;
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BN_CTX_start(ctx);
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if ((e = BN_CTX_get(ctx)) == NULL)
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goto err;
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/* Inverse in constant time with Fermats Little Theorem */
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if (!BN_set_word(e, 2))
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goto err;
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if (!BN_sub(e, group->field, e))
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goto err;
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/*-
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* Exponent e is public.
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* No need for scatter-gather or BN_FLG_CONSTTIME.
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*/
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if (!BN_mod_exp_mont(r, a, e, group->field, ctx, group->field_data1))
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goto err;
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/* throw an error on zero */
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if (BN_is_zero(r)) {
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ECerr(EC_F_EC_GFP_MONT_FIELD_INV, EC_R_CANNOT_INVERT);
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goto err;
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}
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ret = 1;
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err:
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BN_CTX_end(ctx);
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BN_CTX_free(new_ctx);
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return ret;
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}
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int ec_GFp_mont_field_encode(const EC_GROUP *group, BIGNUM *r,
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const BIGNUM *a, BN_CTX *ctx)
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{
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if (group->field_data1 == NULL) {
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ECerr(EC_F_EC_GFP_MONT_FIELD_ENCODE, EC_R_NOT_INITIALIZED);
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return 0;
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}
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return BN_to_montgomery(r, a, (BN_MONT_CTX *)group->field_data1, ctx);
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}
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int ec_GFp_mont_field_decode(const EC_GROUP *group, BIGNUM *r,
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const BIGNUM *a, BN_CTX *ctx)
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{
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if (group->field_data1 == NULL) {
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ECerr(EC_F_EC_GFP_MONT_FIELD_DECODE, EC_R_NOT_INITIALIZED);
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return 0;
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}
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return BN_from_montgomery(r, a, group->field_data1, ctx);
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}
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int ec_GFp_mont_field_set_to_one(const EC_GROUP *group, BIGNUM *r,
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BN_CTX *ctx)
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{
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if (group->field_data2 == NULL) {
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ECerr(EC_F_EC_GFP_MONT_FIELD_SET_TO_ONE, EC_R_NOT_INITIALIZED);
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return 0;
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}
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if (!BN_copy(r, group->field_data2))
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return 0;
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return 1;
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}
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