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- /* Originally written by Bodo Moeller and Nils Larsch for the OpenSSL project.
- * ====================================================================
- * Copyright (c) 1998-2005 The OpenSSL Project. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * 2. 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.
- *
- * 3. All advertising materials mentioning features or use of this
- * software must display the following acknowledgment:
- * "This product includes software developed by the OpenSSL Project
- * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
- *
- * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
- * endorse or promote products derived from this software without
- * prior written permission. For written permission, please contact
- * openssl-core@openssl.org.
- *
- * 5. Products derived from this software may not be called "OpenSSL"
- * nor may "OpenSSL" appear in their names without prior written
- * permission of the OpenSSL Project.
- *
- * 6. Redistributions of any form whatsoever must retain the following
- * acknowledgment:
- * "This product includes software developed by the OpenSSL Project
- * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
- *
- * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
- * EXPRESSED 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 OpenSSL PROJECT OR
- * ITS 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.
- * ====================================================================
- *
- * This product includes cryptographic software written by Eric Young
- * (eay@cryptsoft.com). This product includes software written by Tim
- * Hudson (tjh@cryptsoft.com).
- *
- */
- /* ====================================================================
- * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
- *
- * Portions of the attached software ("Contribution") are developed by
- * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
- *
- * The Contribution is licensed pursuant to the OpenSSL open source
- * license provided above.
- *
- * The elliptic curve binary polynomial software is originally written by
- * Sheueling Chang Shantz and Douglas Stebila of Sun Microsystems
- * Laboratories. */
-
- #include <openssl/ec.h>
-
- #include <openssl/bn.h>
- #include <openssl/err.h>
- #include <openssl/mem.h>
-
- #include "../bn/internal.h"
- #include "../delocate.h"
- #include "internal.h"
-
-
- int ec_GFp_mont_group_init(EC_GROUP *group) {
- int ok;
-
- ok = ec_GFp_simple_group_init(group);
- group->mont = NULL;
- return ok;
- }
-
- void ec_GFp_mont_group_finish(EC_GROUP *group) {
- BN_MONT_CTX_free(group->mont);
- group->mont = NULL;
- ec_GFp_simple_group_finish(group);
- }
-
- int ec_GFp_mont_group_copy(EC_GROUP *dest, const EC_GROUP *src) {
- BN_MONT_CTX_free(dest->mont);
- dest->mont = NULL;
-
- if (!ec_GFp_simple_group_copy(dest, src)) {
- return 0;
- }
-
- if (src->mont != NULL) {
- dest->mont = BN_MONT_CTX_new();
- if (dest->mont == NULL) {
- return 0;
- }
- if (!BN_MONT_CTX_copy(dest->mont, src->mont)) {
- goto err;
- }
- }
-
- return 1;
-
- err:
- BN_MONT_CTX_free(dest->mont);
- dest->mont = NULL;
- return 0;
- }
-
- int ec_GFp_mont_group_set_curve(EC_GROUP *group, const BIGNUM *p,
- const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) {
- BN_CTX *new_ctx = NULL;
- BN_MONT_CTX *mont = NULL;
- int ret = 0;
-
- BN_MONT_CTX_free(group->mont);
- group->mont = NULL;
-
- if (ctx == NULL) {
- ctx = new_ctx = BN_CTX_new();
- if (ctx == NULL) {
- return 0;
- }
- }
-
- mont = BN_MONT_CTX_new();
- if (mont == NULL) {
- goto err;
- }
- if (!BN_MONT_CTX_set(mont, p, ctx)) {
- OPENSSL_PUT_ERROR(EC, ERR_R_BN_LIB);
- goto err;
- }
-
- group->mont = mont;
- mont = NULL;
-
- ret = ec_GFp_simple_group_set_curve(group, p, a, b, ctx);
-
- if (!ret) {
- BN_MONT_CTX_free(group->mont);
- group->mont = NULL;
- }
-
- err:
- BN_CTX_free(new_ctx);
- BN_MONT_CTX_free(mont);
- return ret;
- }
-
- int ec_GFp_mont_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
- const BIGNUM *b, BN_CTX *ctx) {
- if (group->mont == NULL) {
- OPENSSL_PUT_ERROR(EC, EC_R_NOT_INITIALIZED);
- return 0;
- }
-
- return BN_mod_mul_montgomery(r, a, b, group->mont, ctx);
- }
-
- int ec_GFp_mont_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
- BN_CTX *ctx) {
- if (group->mont == NULL) {
- OPENSSL_PUT_ERROR(EC, EC_R_NOT_INITIALIZED);
- return 0;
- }
-
- return BN_mod_mul_montgomery(r, a, a, group->mont, ctx);
- }
-
- int ec_GFp_mont_field_encode(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
- BN_CTX *ctx) {
- if (group->mont == NULL) {
- OPENSSL_PUT_ERROR(EC, EC_R_NOT_INITIALIZED);
- return 0;
- }
-
- return BN_to_montgomery(r, a, group->mont, ctx);
- }
-
- int ec_GFp_mont_field_decode(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
- BN_CTX *ctx) {
- if (group->mont == NULL) {
- OPENSSL_PUT_ERROR(EC, EC_R_NOT_INITIALIZED);
- return 0;
- }
-
- return BN_from_montgomery(r, a, group->mont, ctx);
- }
-
- static int ec_GFp_mont_point_get_affine_coordinates(const EC_GROUP *group,
- const EC_POINT *point,
- BIGNUM *x, BIGNUM *y,
- BN_CTX *ctx) {
- if (EC_POINT_is_at_infinity(group, point)) {
- OPENSSL_PUT_ERROR(EC, EC_R_POINT_AT_INFINITY);
- return 0;
- }
-
- BN_CTX *new_ctx = NULL;
- if (ctx == NULL) {
- ctx = new_ctx = BN_CTX_new();
- if (ctx == NULL) {
- return 0;
- }
- }
-
- int ret = 0;
-
- BN_CTX_start(ctx);
-
- if (BN_cmp(&point->Z, &group->one) == 0) {
- /* |point| is already affine. */
- if (x != NULL && !BN_from_montgomery(x, &point->X, group->mont, ctx)) {
- goto err;
- }
- if (y != NULL && !BN_from_montgomery(y, &point->Y, group->mont, ctx)) {
- goto err;
- }
- } else {
- /* transform (X, Y, Z) into (x, y) := (X/Z^2, Y/Z^3) */
-
- BIGNUM *Z_1 = BN_CTX_get(ctx);
- BIGNUM *Z_2 = BN_CTX_get(ctx);
- BIGNUM *Z_3 = BN_CTX_get(ctx);
- if (Z_1 == NULL ||
- Z_2 == NULL ||
- Z_3 == NULL) {
- goto err;
- }
-
- /* The straightforward way to calculate the inverse of a Montgomery-encoded
- * value where the result is Montgomery-encoded is:
- *
- * |BN_from_montgomery| + invert + |BN_to_montgomery|.
- *
- * This is equivalent, but more efficient, because |BN_from_montgomery|
- * is more efficient (at least in theory) than |BN_to_montgomery|, since it
- * doesn't have to do the multiplication before the reduction.
- *
- * Use Fermat's Little Theorem instead of |BN_mod_inverse_odd| since this
- * inversion may be done as the final step of private key operations.
- * Unfortunately, this is suboptimal for ECDSA verification. */
- if (!BN_from_montgomery(Z_1, &point->Z, group->mont, ctx) ||
- !BN_from_montgomery(Z_1, Z_1, group->mont, ctx) ||
- !bn_mod_inverse_prime(Z_1, Z_1, &group->field, ctx, group->mont)) {
- goto err;
- }
-
- if (!BN_mod_mul_montgomery(Z_2, Z_1, Z_1, group->mont, ctx)) {
- goto err;
- }
-
- /* Instead of using |BN_from_montgomery| to convert the |x| coordinate
- * and then calling |BN_from_montgomery| again to convert the |y|
- * coordinate below, convert the common factor |Z_2| once now, saving one
- * reduction. */
- if (!BN_from_montgomery(Z_2, Z_2, group->mont, ctx)) {
- goto err;
- }
-
- if (x != NULL) {
- if (!BN_mod_mul_montgomery(x, &point->X, Z_2, group->mont, ctx)) {
- goto err;
- }
- }
-
- if (y != NULL) {
- if (!BN_mod_mul_montgomery(Z_3, Z_2, Z_1, group->mont, ctx) ||
- !BN_mod_mul_montgomery(y, &point->Y, Z_3, group->mont, ctx)) {
- goto err;
- }
- }
- }
-
- ret = 1;
-
- err:
- BN_CTX_end(ctx);
- BN_CTX_free(new_ctx);
- return ret;
- }
-
- DEFINE_METHOD_FUNCTION(EC_METHOD, EC_GFp_mont_method) {
- out->group_init = ec_GFp_mont_group_init;
- out->group_finish = ec_GFp_mont_group_finish;
- out->group_copy = ec_GFp_mont_group_copy;
- out->group_set_curve = ec_GFp_mont_group_set_curve;
- out->point_get_affine_coordinates = ec_GFp_mont_point_get_affine_coordinates;
- out->mul = ec_wNAF_mul /* XXX: Not constant time. */;
- out->field_mul = ec_GFp_mont_field_mul;
- out->field_sqr = ec_GFp_mont_field_sqr;
- out->field_encode = ec_GFp_mont_field_encode;
- out->field_decode = ec_GFp_mont_field_decode;
- }
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