/* $OpenBSD: ecp_mont.c,v 1.20 2021/09/08 17:29:21 tb Exp $ */

/*

 * Originally written by Bodo Moeller for the OpenSSL project.

 */

/* ====================================================================

 * Copyright (c) 1998-2001 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 this software developed by SUN MICROSYSTEMS, INC.,

 * and contributed to the OpenSSL project.

 */

#include <openssl/err.h>

#include "ec_lcl.h"

const EC_METHOD *

EC_GFp_mont_method(void)

{

  static const EC_METHOD ret = {

    .flags = EC_FLAGS_DEFAULT_OCT,

    .field_type = NID_X9_62_prime_field,

    .group_init = ec_GFp_mont_group_init,

    .group_finish = ec_GFp_mont_group_finish,

    .group_clear_finish = ec_GFp_mont_group_clear_finish,

    .group_copy = ec_GFp_mont_group_copy,

    .group_set_curve = ec_GFp_mont_group_set_curve,

    .group_get_curve = ec_GFp_simple_group_get_curve,

    .group_get_degree = ec_GFp_simple_group_get_degree,

    .group_order_bits = ec_group_simple_order_bits,

    .group_check_discriminant =

        ec_GFp_simple_group_check_discriminant,

    .point_init = ec_GFp_simple_point_init,

    .point_finish = ec_GFp_simple_point_finish,

    .point_clear_finish = ec_GFp_simple_point_clear_finish,

    .point_copy = ec_GFp_simple_point_copy,

    .point_set_to_infinity = ec_GFp_simple_point_set_to_infinity,

    .point_set_Jprojective_coordinates =

        ec_GFp_simple_set_Jprojective_coordinates,

    .point_get_Jprojective_coordinates =

        ec_GFp_simple_get_Jprojective_coordinates,

    .point_set_affine_coordinates =

        ec_GFp_simple_point_set_affine_coordinates,

    .point_get_affine_coordinates =

        ec_GFp_simple_point_get_affine_coordinates,

    .add = ec_GFp_simple_add,

    .dbl = ec_GFp_simple_dbl,

    .invert = ec_GFp_simple_invert,

    .is_at_infinity = ec_GFp_simple_is_at_infinity,

    .is_on_curve = ec_GFp_simple_is_on_curve,

    .point_cmp = ec_GFp_simple_cmp,

    .make_affine = ec_GFp_simple_make_affine,

    .points_make_affine = ec_GFp_simple_points_make_affine,

    .mul_generator_ct = ec_GFp_simple_mul_generator_ct,

    .mul_single_ct = ec_GFp_simple_mul_single_ct,

    .mul_double_nonct = ec_GFp_simple_mul_double_nonct,

    .field_mul = ec_GFp_mont_field_mul,

    .field_sqr = ec_GFp_mont_field_sqr,

    .field_encode = ec_GFp_mont_field_encode,

    .field_decode = ec_GFp_mont_field_decode,

    .field_set_to_one = ec_GFp_mont_field_set_to_one,

    .blind_coordinates = ec_GFp_simple_blind_coordinates,

  };

  return &ret;

}

int

ec_GFp_mont_group_init(EC_GROUP * group)

{

  int ok;

  ok = ec_GFp_simple_group_init(group);

  group->field_data1 = NULL;

  group->field_data2 = NULL;

  return ok;

}

void

ec_GFp_mont_group_finish(EC_GROUP * group)

{

  BN_MONT_CTX_free(group->field_data1);

  group->field_data1 = NULL;

  BN_free(group->field_data2);

  group->field_data2 = NULL;

  ec_GFp_simple_group_finish(group);

}

void

ec_GFp_mont_group_clear_finish(EC_GROUP * group)

{

  BN_MONT_CTX_free(group->field_data1);

  group->field_data1 = NULL;

  BN_clear_free(group->field_data2);

  group->field_data2 = NULL;

  ec_GFp_simple_group_clear_finish(group);

}

int

ec_GFp_mont_group_copy(EC_GROUP * dest, const EC_GROUP * src)

{

  BN_MONT_CTX_free(dest->field_data1);

  dest->field_data1 = NULL;

  BN_clear_free(dest->field_data2);

  dest->field_data2 = NULL;

  if (!ec_GFp_simple_group_copy(dest, src))

    return 0;

  if (src->field_data1 != NULL) {

    dest->field_data1 = BN_MONT_CTX_new();

    if (dest->field_data1 == NULL)

      return 0;

    if (!BN_MONT_CTX_copy(dest->field_data1, src->field_data1))

      goto err;

  }

  if (src->field_data2 != NULL) {

    dest->field_data2 = BN_dup(src->field_data2);

    if (dest->field_data2 == NULL)

      goto err;

  }

  return 1;

 err:

  if (dest->field_data1 != NULL) {

    BN_MONT_CTX_free(dest->field_data1);

    dest->field_data1 = 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;

  BIGNUM *one = NULL;

  int ret = 0;

  BN_MONT_CTX_free(group->field_data1);

  group->field_data1 = NULL;

  BN_free(group->field_data2);

  group->field_data2 = 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)) {

    ECerror(ERR_R_BN_LIB);

    goto err;

  }

  one = BN_new();

  if (one == NULL)

    goto err;

  if (!BN_to_montgomery(one, BN_value_one(), mont, ctx))

    goto err;

  group->field_data1 = mont;

  mont = NULL;

  group->field_data2 = one;

  one = NULL;

  ret = ec_GFp_simple_group_set_curve(group, p, a, b, ctx);

  if (!ret) {

    BN_MONT_CTX_free(group->field_data1);

    group->field_data1 = NULL;

    BN_free(group->field_data2);

    group->field_data2 = NULL;

  }

 err:

  BN_CTX_free(new_ctx);

  BN_MONT_CTX_free(mont);

  BN_free(one);

  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->field_data1 == NULL) {

    ECerror(EC_R_NOT_INITIALIZED);

    return 0;

  }

  return BN_mod_mul_montgomery(r, a, b, group->field_data1, ctx);

}

int

ec_GFp_mont_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,

    BN_CTX *ctx)

{

  if (group->field_data1 == NULL) {

    ECerror(EC_R_NOT_INITIALIZED);

    return 0;

  }

  return BN_mod_mul_montgomery(r, a, a, group->field_data1, ctx);

}

int

ec_GFp_mont_field_encode(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,

    BN_CTX *ctx)

{

  if (group->field_data1 == NULL) {

    ECerror(EC_R_NOT_INITIALIZED);

    return 0;

  }

  return BN_to_montgomery(r, a, (BN_MONT_CTX *) group->field_data1, ctx);

}

int

ec_GFp_mont_field_decode(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,

    BN_CTX *ctx)

{

  if (group->field_data1 == NULL) {

    ECerror(EC_R_NOT_INITIALIZED);

    return 0;

  }

  return BN_from_montgomery(r, a, group->field_data1, ctx);

}

int

ec_GFp_mont_field_set_to_one(const EC_GROUP *group, BIGNUM *r, BN_CTX *ctx)

{

  if (group->field_data2 == NULL) {

    ECerror(EC_R_NOT_INITIALIZED);

    return 0;

  }

  if (!BN_copy(r, group->field_data2))

    return 0;

  return 1;

}