| 1 | /*
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| 2 | * Copyright 2001-2018 The OpenSSL Project Authors. All Rights Reserved.
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| 3 | * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
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| 4 | *
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| 5 | * Licensed under the OpenSSL license (the "License"). You may not use
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| 6 | * this file except in compliance with the License. You can obtain a copy
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| 7 | * in the file LICENSE in the source distribution or at
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| 8 | * https://www.openssl.org/source/license.html
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| 9 | */
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| 10 |
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| 11 | #include <openssl/err.h>
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| 12 | #include "ec_local.h"
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| 13 |
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| 14 | EC_GROUP *EC_GROUP_new_curve_GFp(const BIGNUM *p, const BIGNUM *a,
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| 15 | const BIGNUM *b, BN_CTX *ctx)
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| 16 | {
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| 17 | const EC_METHOD *meth;
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| 18 | EC_GROUP *ret;
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| 19 |
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| 20 | #if defined(OPENSSL_BN_ASM_MONT)
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| 21 | /*
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| 22 | * This might appear controversial, but the fact is that generic
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| 23 | * prime method was observed to deliver better performance even
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| 24 | * for NIST primes on a range of platforms, e.g.: 60%-15%
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| 25 | * improvement on IA-64, ~25% on ARM, 30%-90% on P4, 20%-25%
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| 26 | * in 32-bit build and 35%--12% in 64-bit build on Core2...
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| 27 | * Coefficients are relative to optimized bn_nist.c for most
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| 28 | * intensive ECDSA verify and ECDH operations for 192- and 521-
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| 29 | * bit keys respectively. Choice of these boundary values is
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| 30 | * arguable, because the dependency of improvement coefficient
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| 31 | * from key length is not a "monotone" curve. For example while
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| 32 | * 571-bit result is 23% on ARM, 384-bit one is -1%. But it's
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| 33 | * generally faster, sometimes "respectfully" faster, sometimes
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| 34 | * "tolerably" slower... What effectively happens is that loop
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| 35 | * with bn_mul_add_words is put against bn_mul_mont, and the
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| 36 | * latter "wins" on short vectors. Correct solution should be
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| 37 | * implementing dedicated NxN multiplication subroutines for
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| 38 | * small N. But till it materializes, let's stick to generic
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| 39 | * prime method...
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| 40 | * <appro>
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| 41 | */
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| 42 | meth = EC_GFp_mont_method();
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| 43 | #else
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| 44 | if (BN_nist_mod_func(p))
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| 45 | meth = EC_GFp_nist_method();
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| 46 | else
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| 47 | meth = EC_GFp_mont_method();
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| 48 | #endif
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| 49 |
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| 50 | ret = EC_GROUP_new(meth);
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| 51 | if (ret == NULL)
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| 52 | return NULL;
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| 53 |
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| 54 | if (!EC_GROUP_set_curve(ret, p, a, b, ctx)) {
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| 55 | EC_GROUP_clear_free(ret);
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| 56 | return NULL;
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| 57 | }
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| 58 |
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| 59 | return ret;
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| 60 | }
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| 61 |
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| 62 | #ifndef OPENSSL_NO_EC2M
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| 63 | EC_GROUP *EC_GROUP_new_curve_GF2m(const BIGNUM *p, const BIGNUM *a,
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| 64 | const BIGNUM *b, BN_CTX *ctx)
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| 65 | {
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| 66 | const EC_METHOD *meth;
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| 67 | EC_GROUP *ret;
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| 68 |
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| 69 | meth = EC_GF2m_simple_method();
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| 70 |
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| 71 | ret = EC_GROUP_new(meth);
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| 72 | if (ret == NULL)
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| 73 | return NULL;
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| 74 |
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| 75 | if (!EC_GROUP_set_curve(ret, p, a, b, ctx)) {
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| 76 | EC_GROUP_clear_free(ret);
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| 77 | return NULL;
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| 78 | }
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| 79 |
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| 80 | return ret;
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| 81 | }
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| 82 | #endif
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