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82 lines
2.6 KiB
C
82 lines
2.6 KiB
C
/*
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* Copyright 2001-2018 The OpenSSL Project Authors. All Rights Reserved.
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* Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
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*
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* Licensed under the OpenSSL license (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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#include <openssl/err.h>
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#include "ec_local.h"
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EC_GROUP *EC_GROUP_new_curve_GFp(const BIGNUM *p, const BIGNUM *a,
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const BIGNUM *b, BN_CTX *ctx)
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{
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const EC_METHOD *meth;
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EC_GROUP *ret;
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#if defined(OPENSSL_BN_ASM_MONT)
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/*
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* This might appear controversial, but the fact is that generic
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* prime method was observed to deliver better performance even
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* for NIST primes on a range of platforms, e.g.: 60%-15%
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* improvement on IA-64, ~25% on ARM, 30%-90% on P4, 20%-25%
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* in 32-bit build and 35%--12% in 64-bit build on Core2...
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* Coefficients are relative to optimized bn_nist.c for most
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* intensive ECDSA verify and ECDH operations for 192- and 521-
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* bit keys respectively. Choice of these boundary values is
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* arguable, because the dependency of improvement coefficient
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* from key length is not a "monotone" curve. For example while
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* 571-bit result is 23% on ARM, 384-bit one is -1%. But it's
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* generally faster, sometimes "respectfully" faster, sometimes
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* "tolerably" slower... What effectively happens is that loop
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* with bn_mul_add_words is put against bn_mul_mont, and the
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* latter "wins" on short vectors. Correct solution should be
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* implementing dedicated NxN multiplication subroutines for
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* small N. But till it materializes, let's stick to generic
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* prime method...
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* <appro>
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*/
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meth = EC_GFp_mont_method();
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#else
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if (BN_nist_mod_func(p))
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meth = EC_GFp_nist_method();
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else
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meth = EC_GFp_mont_method();
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#endif
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ret = EC_GROUP_new(meth);
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if (ret == NULL)
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return NULL;
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if (!EC_GROUP_set_curve(ret, p, a, b, ctx)) {
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EC_GROUP_clear_free(ret);
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return NULL;
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}
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return ret;
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}
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#ifndef OPENSSL_NO_EC2M
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EC_GROUP *EC_GROUP_new_curve_GF2m(const BIGNUM *p, const BIGNUM *a,
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const BIGNUM *b, BN_CTX *ctx)
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{
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const EC_METHOD *meth;
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EC_GROUP *ret;
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meth = EC_GF2m_simple_method();
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ret = EC_GROUP_new(meth);
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if (ret == NULL)
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return NULL;
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if (!EC_GROUP_set_curve(ret, p, a, b, ctx)) {
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EC_GROUP_clear_free(ret);
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return NULL;
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}
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return ret;
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}
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#endif
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