/*

 * Copyright 2001-2021 The OpenSSL Project Authors. All Rights Reserved.

 * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

/*

 * ECDSA low level APIs are deprecated for public use, but still ok for

 * internal use.

 */

#include "internal/deprecated.h"

#include <openssl/err.h>

#include "crypto/bn.h"

#include "ec_local.h"

EC_GROUP *EC_GROUP_new_curve_GFp(const BIGNUM *p, const BIGNUM *a,

                                 const BIGNUM *b, BN_CTX *ctx)

{

    const EC_METHOD *meth;

    EC_GROUP *ret;

#if defined(OPENSSL_BN_ASM_MONT)

    /*

     * This might appear controversial, but the fact is that generic

     * prime method was observed to deliver better performance even

     * for NIST primes on a range of platforms, e.g.: 60%-15%

     * improvement on IA-64, ~25% on ARM, 30%-90% on P4, 20%-25%

     * in 32-bit build and 35%--12% in 64-bit build on Core2...

     * Coefficients are relative to optimized bn_nist.c for most

     * intensive ECDSA verify and ECDH operations for 192- and 521-

     * bit keys respectively. Choice of these boundary values is

     * arguable, because the dependency of improvement coefficient

     * from key length is not a "monotone" curve. For example while

     * 571-bit result is 23% on ARM, 384-bit one is -1%. But it's

     * generally faster, sometimes "respectfully" faster, sometimes

     * "tolerably" slower... What effectively happens is that loop

     * with bn_mul_add_words is put against bn_mul_mont, and the

     * latter "wins" on short vectors. Correct solution should be

     * implementing dedicated NxN multiplication subroutines for

     * small N. But till it materializes, let's stick to generic

     * prime method...

     *                                              <@dot-asm>

     */

    meth = EC_GFp_mont_method();

#else

    if (BN_nist_mod_func(p))

        meth = EC_GFp_nist_method();

    else

        meth = EC_GFp_mont_method();

#endif

    ret = ossl_ec_group_new_ex(ossl_bn_get_libctx(ctx), NULL, meth);

    if (ret == NULL)

        return NULL;

    if (!EC_GROUP_set_curve(ret, p, a, b, ctx)) {

        EC_GROUP_free(ret);

        return NULL;

    }

    return ret;

}

#ifndef OPENSSL_NO_EC2M

EC_GROUP *EC_GROUP_new_curve_GF2m(const BIGNUM *p, const BIGNUM *a,

                                  const BIGNUM *b, BN_CTX *ctx)

{

    const EC_METHOD *meth;

    EC_GROUP *ret;

    meth = EC_GF2m_simple_method();

    ret = ossl_ec_group_new_ex(ossl_bn_get_libctx(ctx), NULL, meth);

    if (ret == NULL)

        return NULL;

    if (!EC_GROUP_set_curve(ret, p, a, b, ctx)) {

        EC_GROUP_free(ret);

        return NULL;

    }

    return ret;

}

#endif