ec2_smpl.c

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/* crypto/ec/ec2_smpl.c */
/* ====================================================================
 * 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
 *    [email protected].
 *
 * 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
 * ([email protected]).  This product includes software written by Tim
 * Hudson ([email protected]).
 *
 */

#include <openssl/err.h>

#include "ec_lcl.h"

#ifndef OPENSSL_NO_EC2M

#ifdef OPENSSL_FIPS
#include <openssl/fips.h>
#endif


const EC_METHOD *EC_GF2m_simple_method(void)
    {
#ifdef OPENSSL_FIPS
    return fips_ec_gf2m_simple_method();
#else
    static const EC_METHOD ret = {
        EC_FLAGS_DEFAULT_OCT,
        NID_X9_62_characteristic_two_field,
        ec_GF2m_simple_group_init,
        ec_GF2m_simple_group_finish,
        ec_GF2m_simple_group_clear_finish,
        ec_GF2m_simple_group_copy,
        ec_GF2m_simple_group_set_curve,
        ec_GF2m_simple_group_get_curve,
        ec_GF2m_simple_group_get_degree,
        ec_GF2m_simple_group_check_discriminant,
        ec_GF2m_simple_point_init,
        ec_GF2m_simple_point_finish,
        ec_GF2m_simple_point_clear_finish,
        ec_GF2m_simple_point_copy,
        ec_GF2m_simple_point_set_to_infinity,
        0 /* set_Jprojective_coordinates_GFp */,
        0 /* get_Jprojective_coordinates_GFp */,
        ec_GF2m_simple_point_set_affine_coordinates,
        ec_GF2m_simple_point_get_affine_coordinates,
        0,0,0,
        ec_GF2m_simple_add,
        ec_GF2m_simple_dbl,
        ec_GF2m_simple_invert,
        ec_GF2m_simple_is_at_infinity,
        ec_GF2m_simple_is_on_curve,
        ec_GF2m_simple_cmp,
        ec_GF2m_simple_make_affine,
        ec_GF2m_simple_points_make_affine,

        /* the following three method functions are defined in ec2_mult.c */
        ec_GF2m_simple_mul,
        ec_GF2m_precompute_mult,
        ec_GF2m_have_precompute_mult,

        ec_GF2m_simple_field_mul,
        ec_GF2m_simple_field_sqr,
        ec_GF2m_simple_field_div,
        0 /* field_encode */,
        0 /* field_decode */,
        0 /* field_set_to_one */ };

    return &ret;
#endif
    }


/* 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))
        {
        ECerr(EC_F_EC_GF2M_SIMPLE_GROUP_SET_CURVE, 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)
            {
            ECerr(EC_F_EC_GF2M_SIMPLE_GROUP_CHECK_DISCRIMINANT, ERR_R_MALLOC_FAILURE);
            goto err;
            }
        }
    BN_CTX_start(ctx);
    b = BN_CTX_get(ctx);
    if (b == 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);
    if (new_ctx != NULL)
        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)
        {
        ECerr(EC_F_EC_GF2M_SIMPLE_POINT_SET_AFFINE_COORDINATES, 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))
        {
        ECerr(EC_F_EC_GF2M_SIMPLE_POINT_GET_AFFINE_COORDINATES, EC_R_POINT_AT_INFINITY);
        return 0;
        }

    if (BN_cmp(&point->Z, BN_value_one())) 
        {
        ECerr(EC_F_EC_GF2M_SIMPLE_POINT_GET_AFFINE_COORDINATES, 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))
        {
        if (!EC_POINT_copy(r, b)) return 0;
        return 1;
        }

    if (EC_POINT_is_at_infinity(group, b))
        {
        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);
    x0 = BN_CTX_get(ctx);
    y0 = BN_CTX_get(ctx);
    x1 = BN_CTX_get(ctx);
    y1 = BN_CTX_get(ctx);
    x2 = BN_CTX_get(ctx);
    y2 = BN_CTX_get(ctx);
    s = BN_CTX_get(ctx);
    t = BN_CTX_get(ctx);
    if (t == 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_GF2m(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_GF2m(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_GF2m(group, r, x2, y2, ctx)) goto err;

    ret = 1;

 err:
    BN_CTX_end(ctx);
    if (new_ctx != NULL)
        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) || 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))
        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);
    y2 = BN_CTX_get(ctx);
    lh = BN_CTX_get(ctx);
    if (lh == 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);
    if (new_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))
        {
        return EC_POINT_is_at_infinity(group, b) ? 0 : 1;
        }

    if (EC_POINT_is_at_infinity(group, b))
        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);
    aX = BN_CTX_get(ctx);
    aY = BN_CTX_get(ctx);
    bX = BN_CTX_get(ctx);
    bY = BN_CTX_get(ctx);
    if (bY == NULL) goto err;

    if (!EC_POINT_get_affine_coordinates_GF2m(group, a, aX, aY, ctx)) goto err;
    if (!EC_POINT_get_affine_coordinates_GF2m(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);
    if (new_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))
        return 1;
    
    if (ctx == NULL)
        {
        ctx = new_ctx = BN_CTX_new();
        if (ctx == NULL)
            return 0;
        }

    BN_CTX_start(ctx);
    x = BN_CTX_get(ctx);
    y = BN_CTX_get(ctx);
    if (y == NULL) goto err;
    
    if (!EC_POINT_get_affine_coordinates_GF2m(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);
    if (new_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