/* $OpenBSD: ec2_smpl.c,v 1.23 2021/09/08 17:29:21 tb Exp $ */

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

 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.

 *

 * The Elliptic Curve Public-Key Crypto Library (ECC Code) included

 * herein is developed by SUN MICROSYSTEMS, INC., and is contributed

 * to the OpenSSL project.

 *

 * The ECC Code is licensed pursuant to the OpenSSL open source

 * license provided below.

 *

 * The software is originally written by Sheueling Chang Shantz and

 * Douglas Stebila of Sun Microsystems Laboratories.

 *

 */

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

 * 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).

 *

 */

#include <openssl/opensslconf.h>

#include <openssl/err.h>

#include "ec_lcl.h"

#ifndef OPENSSL_NO_EC2M

const EC_METHOD *

EC_GF2m_simple_method(void)

{

  static const EC_METHOD ret = {

    .flags = EC_FLAGS_DEFAULT_OCT,

    .field_type = NID_X9_62_characteristic_two_field,

    .group_init = ec_GF2m_simple_group_init,

    .group_finish = ec_GF2m_simple_group_finish,

    .group_clear_finish = ec_GF2m_simple_group_clear_finish,

    .group_copy = ec_GF2m_simple_group_copy,

    .group_set_curve = ec_GF2m_simple_group_set_curve,

    .group_get_curve = ec_GF2m_simple_group_get_curve,

    .group_get_degree = ec_GF2m_simple_group_get_degree,

    .group_order_bits = ec_group_simple_order_bits,

    .group_check_discriminant =

        ec_GF2m_simple_group_check_discriminant,

    .point_init = ec_GF2m_simple_point_init,

    .point_finish = ec_GF2m_simple_point_finish,

    .point_clear_finish = ec_GF2m_simple_point_clear_finish,

    .point_copy = ec_GF2m_simple_point_copy,

    .point_set_to_infinity = ec_GF2m_simple_point_set_to_infinity,

    .point_set_affine_coordinates =

        ec_GF2m_simple_point_set_affine_coordinates,

    .point_get_affine_coordinates =

        ec_GF2m_simple_point_get_affine_coordinates,

    .add = ec_GF2m_simple_add,

    .dbl = ec_GF2m_simple_dbl,

    .invert = ec_GF2m_simple_invert,

    .is_at_infinity = ec_GF2m_simple_is_at_infinity,

    .is_on_curve = ec_GF2m_simple_is_on_curve,

    .point_cmp = ec_GF2m_simple_cmp,

    .make_affine = ec_GF2m_simple_make_affine,

    .points_make_affine = ec_GF2m_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,

    .precompute_mult = ec_GF2m_precompute_mult,

    .have_precompute_mult = ec_GF2m_have_precompute_mult,

    .field_mul = ec_GF2m_simple_field_mul,

    .field_sqr = ec_GF2m_simple_field_sqr,

    .field_div = ec_GF2m_simple_field_div,

    .blind_coordinates = NULL,

  };

  return &ret;

}

/* Initialize a GF(2^m)-based EC_GROUP structure.

 * Note that all other members are handled by EC_GROUP_new.

 */

int 

ec_GF2m_simple_group_init(EC_GROUP * group)

{

  BN_init(&group->field);

  BN_init(&group->a);

  BN_init(&group->b);

  return 1;

}

/* Free a GF(2^m)-based EC_GROUP structure.

 * Note that all other members are handled by EC_GROUP_free.

 */

void 

ec_GF2m_simple_group_finish(EC_GROUP * group)

{

  BN_free(&group->field);

  BN_free(&group->a);

  BN_free(&group->b);

}

/* Clear and free a GF(2^m)-based EC_GROUP structure.

 * Note that all other members are handled by EC_GROUP_clear_free.

 */

void 

ec_GF2m_simple_group_clear_finish(EC_GROUP * group)

{

  BN_clear_free(&group->field);

  BN_clear_free(&group->a);

  BN_clear_free(&group->b);

  group->poly[0] = 0;

  group->poly[1] = 0;

  group->poly[2] = 0;

  group->poly[3] = 0;

  group->poly[4] = 0;

  group->poly[5] = -1;

}

/* Copy a GF(2^m)-based EC_GROUP structure.

 * Note that all other members are handled by EC_GROUP_copy.

 */

int 

ec_GF2m_simple_group_copy(EC_GROUP * dest, const EC_GROUP * src)

{

  int i;

  if (!BN_copy(&dest->field, &src->field))

    return 0;

  if (!BN_copy(&dest->a, &src->a))

    return 0;

  if (!BN_copy(&dest->b, &src->b))

    return 0;

  dest->poly[0] = src->poly[0];

  dest->poly[1] = src->poly[1];

  dest->poly[2] = src->poly[2];

  dest->poly[3] = src->poly[3];

  dest->poly[4] = src->poly[4];

  dest->poly[5] = src->poly[5];

  if (bn_wexpand(&dest->a, (int) (dest->poly[0] + BN_BITS2 - 1) / BN_BITS2) == NULL)

    return 0;

  if (bn_wexpand(&dest->b, (int) (dest->poly[0] + BN_BITS2 - 1) / BN_BITS2) == NULL)

    return 0;

  for (i = dest->a.top; i < dest->a.dmax; i++)

    dest->a.d[i] = 0;

  for (i = dest->b.top; i < dest->b.dmax; i++)

    dest->b.d[i] = 0;

  return 1;

}

/* Set the curve parameters of an EC_GROUP structure. */

int 

ec_GF2m_simple_group_set_curve(EC_GROUP * group,

    const BIGNUM * p, const BIGNUM * a, const BIGNUM * b, BN_CTX * ctx)

{

  int ret = 0, i;

  /* group->field */

  if (!BN_copy(&group->field, p))

    goto err;

  i = BN_GF2m_poly2arr(&group->field, group->poly, 6) - 1;

  if ((i != 5) && (i != 3)) {

    ECerror(EC_R_UNSUPPORTED_FIELD);

    goto err;

  }

  /* group->a */

  if (!BN_GF2m_mod_arr(&group->a, a, group->poly))

    goto err;

  if (bn_wexpand(&group->a, (int) (group->poly[0] + BN_BITS2 - 1) / BN_BITS2) == NULL)

    goto err;

  for (i = group->a.top; i < group->a.dmax; i++)

    group->a.d[i] = 0;

  /* group->b */

  if (!BN_GF2m_mod_arr(&group->b, b, group->poly))

    goto err;

  if (bn_wexpand(&group->b, (int) (group->poly[0] + BN_BITS2 - 1) / BN_BITS2) == NULL)

    goto err;

  for (i = group->b.top; i < group->b.dmax; i++)

    group->b.d[i] = 0;

  ret = 1;

 err:

  return ret;

}

/* Get the curve parameters of an EC_GROUP structure.

 * If p, a, or b are NULL then there values will not be set but the method will return with success.

 */

int 

ec_GF2m_simple_group_get_curve(const EC_GROUP *group,

    BIGNUM *p, BIGNUM *a, BIGNUM *b, BN_CTX *ctx)

{

  int ret = 0;

  if (p != NULL) {

    if (!BN_copy(p, &group->field))

      return 0;

  }

  if (a != NULL) {

    if (!BN_copy(a, &group->a))

      goto err;

  }

  if (b != NULL) {

    if (!BN_copy(b, &group->b))

      goto err;

  }

  ret = 1;

 err:

  return ret;

}

/* Gets the degree of the field.  For a curve over GF(2^m) this is the value m. */

int 

ec_GF2m_simple_group_get_degree(const EC_GROUP * group)

{

  return BN_num_bits(&group->field) - 1;

}

/* Checks the discriminant of the curve.

 * y^2 + x*y = x^3 + a*x^2 + b is an elliptic curve <=> b != 0 (mod p)

 */

int 

ec_GF2m_simple_group_check_discriminant(const EC_GROUP * group, BN_CTX * ctx)

{

  int ret = 0;

  BIGNUM *b;

  BN_CTX *new_ctx = NULL;

  if (ctx == NULL) {

    ctx = new_ctx = BN_CTX_new();

    if (ctx == NULL) {

      ECerror(ERR_R_MALLOC_FAILURE);

      goto err;

    }

  }

  BN_CTX_start(ctx);

  if ((b = BN_CTX_get(ctx)) == NULL)

    goto err;

  if (!BN_GF2m_mod_arr(b, &group->b, group->poly))

    goto err;

  /*

   * check the discriminant: y^2 + x*y = x^3 + a*x^2 + b is an elliptic

   * curve <=> b != 0 (mod p)

   */

  if (BN_is_zero(b))

    goto err;

  ret = 1;

 err:

  if (ctx != NULL)

    BN_CTX_end(ctx);

  BN_CTX_free(new_ctx);

  return ret;

}

/* Initializes an EC_POINT. */

int 

ec_GF2m_simple_point_init(EC_POINT * point)

{

  BN_init(&point->X);

  BN_init(&point->Y);

  BN_init(&point->Z);

  return 1;

}

/* Frees an EC_POINT. */

void 

ec_GF2m_simple_point_finish(EC_POINT * point)

{

  BN_free(&point->X);

  BN_free(&point->Y);

  BN_free(&point->Z);

}

/* Clears and frees an EC_POINT. */

void 

ec_GF2m_simple_point_clear_finish(EC_POINT * point)

{

  BN_clear_free(&point->X);

  BN_clear_free(&point->Y);

  BN_clear_free(&point->Z);

  point->Z_is_one = 0;

}

/* Copy the contents of one EC_POINT into another.  Assumes dest is initialized. */

int 

ec_GF2m_simple_point_copy(EC_POINT * dest, const EC_POINT * src)

{

  if (!BN_copy(&dest->X, &src->X))

    return 0;

  if (!BN_copy(&dest->Y, &src->Y))

    return 0;

  if (!BN_copy(&dest->Z, &src->Z))

    return 0;

  dest->Z_is_one = src->Z_is_one;

  return 1;

}

/* Set an EC_POINT to the point at infinity.

 * A point at infinity is represented by having Z=0.

 */

int 

ec_GF2m_simple_point_set_to_infinity(const EC_GROUP * group, EC_POINT * point)

{

  point->Z_is_one = 0;

  BN_zero(&point->Z);

  return 1;

}

/* Set the coordinates of an EC_POINT using affine coordinates.

 * Note that the simple implementation only uses affine coordinates.

 */

int 

ec_GF2m_simple_point_set_affine_coordinates(const EC_GROUP * group, EC_POINT * point,

    const BIGNUM * x, const BIGNUM * y, BN_CTX * ctx)

{

  int ret = 0;

  if (x == NULL || y == NULL) {

    ECerror(ERR_R_PASSED_NULL_PARAMETER);

    return 0;

  }

  if (!BN_copy(&point->X, x))

    goto err;

  BN_set_negative(&point->X, 0);

  if (!BN_copy(&point->Y, y))

    goto err;

  BN_set_negative(&point->Y, 0);

  if (!BN_copy(&point->Z, BN_value_one()))

    goto err;

  BN_set_negative(&point->Z, 0);

  point->Z_is_one = 1;

  ret = 1;

 err:

  return ret;

}

/* Gets the affine coordinates of an EC_POINT.

 * Note that the simple implementation only uses affine coordinates.

 */

int 

ec_GF2m_simple_point_get_affine_coordinates(const EC_GROUP *group,

    const EC_POINT *point, BIGNUM *x, BIGNUM *y, BN_CTX *ctx)

{

  int ret = 0;

  if (EC_POINT_is_at_infinity(group, point) > 0) {

    ECerror(EC_R_POINT_AT_INFINITY);

    return 0;

  }

  if (BN_cmp(&point->Z, BN_value_one())) {

    ECerror(ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);

    return 0;

  }

  if (x != NULL) {

    if (!BN_copy(x, &point->X))

      goto err;

    BN_set_negative(x, 0);

  }

  if (y != NULL) {

    if (!BN_copy(y, &point->Y))

      goto err;

    BN_set_negative(y, 0);

  }

  ret = 1;

 err:

  return ret;

}

/* Computes a + b and stores the result in r.  r could be a or b, a could be b.

 * Uses algorithm A.10.2 of IEEE P1363.

 */

int 

ec_GF2m_simple_add(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a,

    const EC_POINT *b, BN_CTX *ctx)

{

  BN_CTX *new_ctx = NULL;

  BIGNUM *x0, *y0, *x1, *y1, *x2, *y2, *s, *t;

  int ret = 0;

  if (EC_POINT_is_at_infinity(group, a) > 0) {

    if (!EC_POINT_copy(r, b))

      return 0;

    return 1;

  }

  if (EC_POINT_is_at_infinity(group, b) > 0) {

    if (!EC_POINT_copy(r, a))

      return 0;

    return 1;

  }

  if (ctx == NULL) {

    ctx = new_ctx = BN_CTX_new();

    if (ctx == NULL)

      return 0;

  }

  BN_CTX_start(ctx);

  if ((x0 = BN_CTX_get(ctx)) == NULL)

    goto err;

  if ((y0 = BN_CTX_get(ctx)) == NULL)

    goto err;

  if ((x1 = BN_CTX_get(ctx)) == NULL)

    goto err;

  if ((y1 = BN_CTX_get(ctx)) == NULL)

    goto err;

  if ((x2 = BN_CTX_get(ctx)) == NULL)

    goto err;

  if ((y2 = BN_CTX_get(ctx)) == NULL)

    goto err;

  if ((s = BN_CTX_get(ctx)) == NULL)

    goto err;

  if ((t = BN_CTX_get(ctx)) == NULL)

    goto err;

  if (a->Z_is_one) {

    if (!BN_copy(x0, &a->X))

      goto err;

    if (!BN_copy(y0, &a->Y))

      goto err;

  } else {

    if (!EC_POINT_get_affine_coordinates(group, a, x0, y0, ctx))

      goto err;

  }

  if (b->Z_is_one) {

    if (!BN_copy(x1, &b->X))

      goto err;

    if (!BN_copy(y1, &b->Y))

      goto err;

  } else {

    if (!EC_POINT_get_affine_coordinates(group, b, x1, y1, ctx))

      goto err;

  }

  if (BN_GF2m_cmp(x0, x1)) {

    if (!BN_GF2m_add(t, x0, x1))

      goto err;

    if (!BN_GF2m_add(s, y0, y1))

      goto err;

    if (!group->meth->field_div(group, s, s, t, ctx))

      goto err;

    if (!group->meth->field_sqr(group, x2, s, ctx))

      goto err;

    if (!BN_GF2m_add(x2, x2, &group->a))

      goto err;

    if (!BN_GF2m_add(x2, x2, s))

      goto err;

    if (!BN_GF2m_add(x2, x2, t))

      goto err;

  } else {

    if (BN_GF2m_cmp(y0, y1) || BN_is_zero(x1)) {

      if (!EC_POINT_set_to_infinity(group, r))

        goto err;

      ret = 1;

      goto err;

    }

    if (!group->meth->field_div(group, s, y1, x1, ctx))

      goto err;

    if (!BN_GF2m_add(s, s, x1))

      goto err;

    if (!group->meth->field_sqr(group, x2, s, ctx))

      goto err;

    if (!BN_GF2m_add(x2, x2, s))

      goto err;

    if (!BN_GF2m_add(x2, x2, &group->a))

      goto err;

  }

  if (!BN_GF2m_add(y2, x1, x2))

    goto err;

  if (!group->meth->field_mul(group, y2, y2, s, ctx))

    goto err;

  if (!BN_GF2m_add(y2, y2, x2))

    goto err;

  if (!BN_GF2m_add(y2, y2, y1))

    goto err;

  if (!EC_POINT_set_affine_coordinates(group, r, x2, y2, ctx))

    goto err;

  ret = 1;

 err:

  BN_CTX_end(ctx);

  BN_CTX_free(new_ctx);

  return ret;

}

/* Computes 2 * a and stores the result in r.  r could be a.

 * Uses algorithm A.10.2 of IEEE P1363.

 */

int 

ec_GF2m_simple_dbl(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a,

    BN_CTX *ctx)

{

  return ec_GF2m_simple_add(group, r, a, a, ctx);

}

int 

ec_GF2m_simple_invert(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx)

{

  if (EC_POINT_is_at_infinity(group, point) > 0 || BN_is_zero(&point->Y))

    /* point is its own inverse */

    return 1;

  if (!EC_POINT_make_affine(group, point, ctx))

    return 0;

  return BN_GF2m_add(&point->Y, &point->X, &point->Y);

}

/* Indicates whether the given point is the point at infinity. */

int 

ec_GF2m_simple_is_at_infinity(const EC_GROUP *group, const EC_POINT *point)

{

  return BN_is_zero(&point->Z);

}

/* Determines whether the given EC_POINT is an actual point on the curve defined

 * in the EC_GROUP.  A point is valid if it satisfies the Weierstrass equation:

 *      y^2 + x*y = x^3 + a*x^2 + b.

 */

int 

ec_GF2m_simple_is_on_curve(const EC_GROUP *group, const EC_POINT *point, BN_CTX *ctx)

{

  int ret = -1;

  BN_CTX *new_ctx = NULL;

  BIGNUM *lh, *y2;

  int (*field_mul) (const EC_GROUP *, BIGNUM *, const BIGNUM *, const BIGNUM *, BN_CTX *);

  int (*field_sqr) (const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *);

  if (EC_POINT_is_at_infinity(group, point) > 0)

    return 1;

  field_mul = group->meth->field_mul;

  field_sqr = group->meth->field_sqr;

  /* only support affine coordinates */

  if (!point->Z_is_one)

    return -1;

  if (ctx == NULL) {

    ctx = new_ctx = BN_CTX_new();

    if (ctx == NULL)

      return -1;

  }

  BN_CTX_start(ctx);

  if ((y2 = BN_CTX_get(ctx)) == NULL)

    goto err;

  if ((lh = BN_CTX_get(ctx)) == NULL)

    goto err;

  /*

   * We have a curve defined by a Weierstrass equation y^2 + x*y = x^3

   * + a*x^2 + b. <=> x^3 + a*x^2 + x*y + b + y^2 = 0 <=> ((x + a) * x

   * + y ) * x + b + y^2 = 0

   */

  if (!BN_GF2m_add(lh, &point->X, &group->a))

    goto err;

  if (!field_mul(group, lh, lh, &point->X, ctx))

    goto err;

  if (!BN_GF2m_add(lh, lh, &point->Y))

    goto err;

  if (!field_mul(group, lh, lh, &point->X, ctx))

    goto err;

  if (!BN_GF2m_add(lh, lh, &group->b))

    goto err;

  if (!field_sqr(group, y2, &point->Y, ctx))

    goto err;

  if (!BN_GF2m_add(lh, lh, y2))

    goto err;

  ret = BN_is_zero(lh);

 err:

  if (ctx)

    BN_CTX_end(ctx);

  BN_CTX_free(new_ctx);

  return ret;

}

/* Indicates whether two points are equal.

 * Return values:

 *  -1   error

 *   0   equal (in affine coordinates)

 *   1   not equal

 */

int 

ec_GF2m_simple_cmp(const EC_GROUP *group, const EC_POINT *a,

    const EC_POINT *b, BN_CTX *ctx)

{

  BIGNUM *aX, *aY, *bX, *bY;

  BN_CTX *new_ctx = NULL;

  int ret = -1;

  if (EC_POINT_is_at_infinity(group, a) > 0) {

    return EC_POINT_is_at_infinity(group, b) > 0 ? 0 : 1;

  }

  if (EC_POINT_is_at_infinity(group, b) > 0)

    return 1;

  if (a->Z_is_one && b->Z_is_one) {

    return ((BN_cmp(&a->X, &b->X) == 0) && BN_cmp(&a->Y, &b->Y) == 0) ? 0 : 1;

  }

  if (ctx == NULL) {

    ctx = new_ctx = BN_CTX_new();

    if (ctx == NULL)

      return -1;

  }

  BN_CTX_start(ctx);

  if ((aX = BN_CTX_get(ctx)) == NULL)

    goto err;

  if ((aY = BN_CTX_get(ctx)) == NULL)

    goto err;

  if ((bX = BN_CTX_get(ctx)) == NULL)

    goto err;

  if ((bY = BN_CTX_get(ctx)) == NULL)

    goto err;

  if (!EC_POINT_get_affine_coordinates(group, a, aX, aY, ctx))

    goto err;

  if (!EC_POINT_get_affine_coordinates(group, b, bX, bY, ctx))

    goto err;

  ret = ((BN_cmp(aX, bX) == 0) && BN_cmp(aY, bY) == 0) ? 0 : 1;

 err:

  if (ctx)

    BN_CTX_end(ctx);

  BN_CTX_free(new_ctx);

  return ret;

}

/* Forces the given EC_POINT to internally use affine coordinates. */

int 

ec_GF2m_simple_make_affine(const EC_GROUP * group, EC_POINT * point, BN_CTX * ctx)

{

  BN_CTX *new_ctx = NULL;

  BIGNUM *x, *y;

  int ret = 0;

  if (point->Z_is_one || EC_POINT_is_at_infinity(group, point) > 0)

    return 1;

  if (ctx == NULL) {

    ctx = new_ctx = BN_CTX_new();

    if (ctx == NULL)

      return 0;

  }

  BN_CTX_start(ctx);

  if ((x = BN_CTX_get(ctx)) == NULL)

    goto err;

  if ((y = BN_CTX_get(ctx)) == NULL)

    goto err;

  if (!EC_POINT_get_affine_coordinates(group, point, x, y, ctx))

    goto err;

  if (!BN_copy(&point->X, x))

    goto err;

  if (!BN_copy(&point->Y, y))

    goto err;

  if (!BN_one(&point->Z))

    goto err;

  ret = 1;

 err:

  if (ctx)

    BN_CTX_end(ctx);

  BN_CTX_free(new_ctx);

  return ret;

}

/* Forces each of the EC_POINTs in the given array to use affine coordinates. */

int 

ec_GF2m_simple_points_make_affine(const EC_GROUP *group, size_t num,

    EC_POINT *points[], BN_CTX *ctx)

{

  size_t i;

  for (i = 0; i < num; i++) {

    if (!group->meth->make_affine(group, points[i], ctx))

      return 0;

  }

  return 1;

}

/* Wrapper to simple binary polynomial field multiplication implementation. */

int 

ec_GF2m_simple_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,

    const BIGNUM *b, BN_CTX *ctx)

{

  return BN_GF2m_mod_mul_arr(r, a, b, group->poly, ctx);

}

/* Wrapper to simple binary polynomial field squaring implementation. */

int 

ec_GF2m_simple_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,

    BN_CTX *ctx)

{

  return BN_GF2m_mod_sqr_arr(r, a, group->poly, ctx);

}

/* Wrapper to simple binary polynomial field division implementation. */

int 

ec_GF2m_simple_field_div(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,

    const BIGNUM *b, BN_CTX *ctx)

{

  return BN_GF2m_mod_div(r, a, b, &group->field, ctx);

}

#endif