/* $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