pineapple/externals/libressl/crypto/ec/ec_cvt.c

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2020-12-28 16:15:37 +01:00
/* $OpenBSD: ec_cvt.c,v 1.6 2014/07/10 22:45:57 jsing Exp $ */
/*
* Originally written by Bodo Moeller for the OpenSSL project.
*/
/* ====================================================================
* Copyright (c) 1998-2002 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 the attached software ("Contribution") are developed by
* SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
*
* The Contribution is licensed pursuant to the OpenSSL open source
* license provided above.
*
* The elliptic curve binary polynomial software is originally written by
* Sheueling Chang Shantz and Douglas Stebila of Sun Microsystems Laboratories.
*
*/
#include <openssl/opensslconf.h>
#include <openssl/err.h>
#include "ec_lcl.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...
* <appro>
*/
meth = EC_GFp_mont_method();
#else
meth = EC_GFp_nist_method();
#endif
ret = EC_GROUP_new(meth);
if (ret == NULL)
return NULL;
if (!EC_GROUP_set_curve_GFp(ret, p, a, b, ctx)) {
unsigned long err;
err = ERR_peek_last_error();
if (!(ERR_GET_LIB(err) == ERR_LIB_EC &&
((ERR_GET_REASON(err) == EC_R_NOT_A_NIST_PRIME) ||
(ERR_GET_REASON(err) == EC_R_NOT_A_SUPPORTED_NIST_PRIME)))) {
/* real error */
EC_GROUP_clear_free(ret);
return NULL;
}
/* not an actual error, we just cannot use EC_GFp_nist_method */
ERR_clear_error();
EC_GROUP_clear_free(ret);
meth = EC_GFp_mont_method();
ret = EC_GROUP_new(meth);
if (ret == NULL)
return NULL;
if (!EC_GROUP_set_curve_GFp(ret, p, a, b, ctx)) {
EC_GROUP_clear_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 = EC_GROUP_new(meth);
if (ret == NULL)
return NULL;
if (!EC_GROUP_set_curve_GF2m(ret, p, a, b, ctx)) {
EC_GROUP_clear_free(ret);
return NULL;
}
return ret;
}
#endif