1/* crypto/ec/ec_cvt.c */ 2/* 3 * Originally written by Bodo Moeller for the OpenSSL project. 4 */ 5/* ==================================================================== 6 * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in 17 * the documentation and/or other materials provided with the 18 * distribution. 19 * 20 * 3. All advertising materials mentioning features or use of this 21 * software must display the following acknowledgment: 22 * "This product includes software developed by the OpenSSL Project 23 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 24 * 25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 26 * endorse or promote products derived from this software without 27 * prior written permission. For written permission, please contact 28 * openssl-core@openssl.org. 29 * 30 * 5. Products derived from this software may not be called "OpenSSL" 31 * nor may "OpenSSL" appear in their names without prior written 32 * permission of the OpenSSL Project. 33 * 34 * 6. Redistributions of any form whatsoever must retain the following 35 * acknowledgment: 36 * "This product includes software developed by the OpenSSL Project 37 * for use in the OpenSSL Toolkit (http://www.openssl.org/)" 38 * 39 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 48 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 49 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 50 * OF THE POSSIBILITY OF SUCH DAMAGE. 51 * ==================================================================== 52 * 53 * This product includes cryptographic software written by Eric Young 54 * (eay@cryptsoft.com). This product includes software written by Tim 55 * Hudson (tjh@cryptsoft.com). 56 * 57 */ 58/* ==================================================================== 59 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED. 60 * 61 * Portions of the attached software ("Contribution") are developed by 62 * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project. 63 * 64 * The Contribution is licensed pursuant to the OpenSSL open source 65 * license provided above. 66 * 67 * The elliptic curve binary polynomial software is originally written by 68 * Sheueling Chang Shantz and Douglas Stebila of Sun Microsystems Laboratories. 69 * 70 */ 71 72#include <openssl/err.h> 73#include "ec_lcl.h" 74 75 76EC_GROUP *EC_GROUP_new_curve_GFp(const BIGNUM *p, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) 77 { 78 const EC_METHOD *meth; 79 EC_GROUP *ret; 80 81#if defined(OPENSSL_BN_ASM_MONT) 82 /* 83 * This might appear controversial, but the fact is that generic 84 * prime method was observed to deliver better performance even 85 * for NIST primes on a range of platforms, e.g.: 60%-15% 86 * improvement on IA-64, ~25% on ARM, 30%-90% on P4, 20%-25% 87 * in 32-bit build and 35%--12% in 64-bit build on Core2... 88 * Coefficients are relative to optimized bn_nist.c for most 89 * intensive ECDSA verify and ECDH operations for 192- and 521- 90 * bit keys respectively. Choice of these boundary values is 91 * arguable, because the dependency of improvement coefficient 92 * from key length is not a "monotone" curve. For example while 93 * 571-bit result is 23% on ARM, 384-bit one is -1%. But it's 94 * generally faster, sometimes "respectfully" faster, sometimes 95 * "tolerably" slower... What effectively happens is that loop 96 * with bn_mul_add_words is put against bn_mul_mont, and the 97 * latter "wins" on short vectors. Correct solution should be 98 * implementing dedicated NxN multiplication subroutines for 99 * small N. But till it materializes, let's stick to generic 100 * prime method... 101 * <appro> 102 */ 103 meth = EC_GFp_mont_method(); 104#else 105 meth = EC_GFp_nist_method(); 106#endif 107 108 ret = EC_GROUP_new(meth); 109 if (ret == NULL) 110 return NULL; 111 112 if (!EC_GROUP_set_curve_GFp(ret, p, a, b, ctx)) 113 { 114 unsigned long err; 115 116 err = ERR_peek_last_error(); 117 118 if (!(ERR_GET_LIB(err) == ERR_LIB_EC && 119 ((ERR_GET_REASON(err) == EC_R_NOT_A_NIST_PRIME) || 120 (ERR_GET_REASON(err) == EC_R_NOT_A_SUPPORTED_NIST_PRIME)))) 121 { 122 /* real error */ 123 124 EC_GROUP_clear_free(ret); 125 return NULL; 126 } 127 128 129 /* not an actual error, we just cannot use EC_GFp_nist_method */ 130 131 ERR_clear_error(); 132 133 EC_GROUP_clear_free(ret); 134 meth = EC_GFp_mont_method(); 135 136 ret = EC_GROUP_new(meth); 137 if (ret == NULL) 138 return NULL; 139 140 if (!EC_GROUP_set_curve_GFp(ret, p, a, b, ctx)) 141 { 142 EC_GROUP_clear_free(ret); 143 return NULL; 144 } 145 } 146 147 return ret; 148 } 149 150#ifndef OPENSSL_NO_EC2M 151EC_GROUP *EC_GROUP_new_curve_GF2m(const BIGNUM *p, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) 152 { 153 const EC_METHOD *meth; 154 EC_GROUP *ret; 155 156 meth = EC_GF2m_simple_method(); 157 158 ret = EC_GROUP_new(meth); 159 if (ret == NULL) 160 return NULL; 161 162 if (!EC_GROUP_set_curve_GF2m(ret, p, a, b, ctx)) 163 { 164 EC_GROUP_clear_free(ret); 165 return NULL; 166 } 167 168 return ret; 169 } 170#endif 171