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 14EC_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 63EC_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 83