| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2001-2018 The OpenSSL Project Authors. All Rights Reserved. |
| 3 | * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved |
| 4 | * |
| 5 | * Licensed under the OpenSSL license (the "License"). You may not use |
| 6 | * this file except in compliance with the License. You can obtain a copy |
| 7 | * in the file LICENSE in the source distribution or at |
| 8 | * https://www.openssl.org/source/license.html |
| 9 | */ |
| 10 | |
| 11 | #include <openssl/err.h> |
| 12 | #include "ec_local.h" |
| 13 | |
| 14 | EC_GROUP *EC_GROUP_new_curve_GFp(const BIGNUM *p, const BIGNUM *a, |
| 15 | const BIGNUM *b, BN_CTX *ctx) |
| 16 | { |
| 17 | const EC_METHOD *meth; |
| 18 | EC_GROUP *ret; |
| 19 | |
| 20 | #if defined(OPENSSL_BN_ASM_MONT) |
| 21 | /* |
| 22 | * This might appear controversial, but the fact is that generic |
| 23 | * prime method was observed to deliver better performance even |
| 24 | * for NIST primes on a range of platforms, e.g.: 60%-15% |
| 25 | * improvement on IA-64, ~25% on ARM, 30%-90% on P4, 20%-25% |
| 26 | * in 32-bit build and 35%--12% in 64-bit build on Core2... |
| 27 | * Coefficients are relative to optimized bn_nist.c for most |
| 28 | * intensive ECDSA verify and ECDH operations for 192- and 521- |
| 29 | * bit keys respectively. Choice of these boundary values is |
| 30 | * arguable, because the dependency of improvement coefficient |
| 31 | * from key length is not a "monotone" curve. For example while |
| 32 | * 571-bit result is 23% on ARM, 384-bit one is -1%. But it's |
| 33 | * generally faster, sometimes "respectfully" faster, sometimes |
| 34 | * "tolerably" slower... What effectively happens is that loop |
| 35 | * with bn_mul_add_words is put against bn_mul_mont, and the |
| 36 | * latter "wins" on short vectors. Correct solution should be |
| 37 | * implementing dedicated NxN multiplication subroutines for |
| 38 | * small N. But till it materializes, let's stick to generic |
| 39 | * prime method... |
| 40 | * <appro> |
| 41 | */ |
| 42 | meth = EC_GFp_mont_method(); |
| 43 | #else |
| 44 | if (BN_nist_mod_func(p)) |
| 45 | meth = EC_GFp_nist_method(); |
| 46 | else |
| 47 | meth = EC_GFp_mont_method(); |
| 48 | #endif |
| 49 | |
| 50 | ret = EC_GROUP_new(meth); |
| 51 | if (ret == NULL) |
| 52 | return NULL; |
| 53 | |
| 54 | if (!EC_GROUP_set_curve(ret, p, a, b, ctx)) { |
| 55 | EC_GROUP_clear_free(ret); |
| 56 | return NULL; |
| 57 | } |
| 58 | |
| 59 | return ret; |
| 60 | } |
| 61 | |
| 62 | #ifndef OPENSSL_NO_EC2M |
| 63 | EC_GROUP *EC_GROUP_new_curve_GF2m(const BIGNUM *p, const BIGNUM *a, |
| 64 | const BIGNUM *b, BN_CTX *ctx) |
| 65 | { |
| 66 | const EC_METHOD *meth; |
| 67 | EC_GROUP *ret; |
| 68 | |
| 69 | meth = EC_GF2m_simple_method(); |
| 70 | |
| 71 | ret = EC_GROUP_new(meth); |
| 72 | if (ret == NULL) |
| 73 | return NULL; |
| 74 | |
| 75 | if (!EC_GROUP_set_curve(ret, p, a, b, ctx)) { |
| 76 | EC_GROUP_clear_free(ret); |
| 77 | return NULL; |
| 78 | } |
| 79 | |
| 80 | return ret; |
| 81 | } |
| 82 | #endif |