Line data Source code
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 : #ifdef OPENSSL_FIPS
76 : # include <openssl/fips.h>
77 : #endif
78 :
79 1242 : EC_GROUP *EC_GROUP_new_curve_GFp(const BIGNUM *p, const BIGNUM *a,
80 : const BIGNUM *b, BN_CTX *ctx)
81 : {
82 : const EC_METHOD *meth;
83 : EC_GROUP *ret;
84 :
85 : #ifdef OPENSSL_FIPS
86 : if (FIPS_mode())
87 : return FIPS_ec_group_new_curve_gfp(p, a, b, ctx);
88 : #endif
89 : #if defined(OPENSSL_BN_ASM_MONT)
90 : /*
91 : * This might appear controversial, but the fact is that generic
92 : * prime method was observed to deliver better performance even
93 : * for NIST primes on a range of platforms, e.g.: 60%-15%
94 : * improvement on IA-64, ~25% on ARM, 30%-90% on P4, 20%-25%
95 : * in 32-bit build and 35%--12% in 64-bit build on Core2...
96 : * Coefficients are relative to optimized bn_nist.c for most
97 : * intensive ECDSA verify and ECDH operations for 192- and 521-
98 : * bit keys respectively. Choice of these boundary values is
99 : * arguable, because the dependency of improvement coefficient
100 : * from key length is not a "monotone" curve. For example while
101 : * 571-bit result is 23% on ARM, 384-bit one is -1%. But it's
102 : * generally faster, sometimes "respectfully" faster, sometimes
103 : * "tolerably" slower... What effectively happens is that loop
104 : * with bn_mul_add_words is put against bn_mul_mont, and the
105 : * latter "wins" on short vectors. Correct solution should be
106 : * implementing dedicated NxN multiplication subroutines for
107 : * small N. But till it materializes, let's stick to generic
108 : * prime method...
109 : * <appro>
110 : */
111 : meth = EC_GFp_mont_method();
112 : #else
113 1242 : meth = EC_GFp_nist_method();
114 : #endif
115 :
116 1242 : ret = EC_GROUP_new(meth);
117 1242 : if (ret == NULL)
118 : return NULL;
119 :
120 1242 : if (!EC_GROUP_set_curve_GFp(ret, p, a, b, ctx)) {
121 : unsigned long err;
122 :
123 0 : err = ERR_peek_last_error();
124 :
125 0 : if (!(ERR_GET_LIB(err) == ERR_LIB_EC &&
126 0 : ((ERR_GET_REASON(err) == EC_R_NOT_A_NIST_PRIME) ||
127 : (ERR_GET_REASON(err) == EC_R_NOT_A_SUPPORTED_NIST_PRIME)))) {
128 : /* real error */
129 :
130 0 : EC_GROUP_clear_free(ret);
131 0 : return NULL;
132 : }
133 :
134 : /*
135 : * not an actual error, we just cannot use EC_GFp_nist_method
136 : */
137 :
138 0 : ERR_clear_error();
139 :
140 0 : EC_GROUP_clear_free(ret);
141 0 : meth = EC_GFp_mont_method();
142 :
143 0 : ret = EC_GROUP_new(meth);
144 0 : if (ret == NULL)
145 : return NULL;
146 :
147 0 : if (!EC_GROUP_set_curve_GFp(ret, p, a, b, ctx)) {
148 0 : EC_GROUP_clear_free(ret);
149 0 : return NULL;
150 : }
151 : }
152 :
153 1242 : return ret;
154 : }
155 :
156 : #ifndef OPENSSL_NO_EC2M
157 0 : EC_GROUP *EC_GROUP_new_curve_GF2m(const BIGNUM *p, const BIGNUM *a,
158 : const BIGNUM *b, BN_CTX *ctx)
159 : {
160 : const EC_METHOD *meth;
161 : EC_GROUP *ret;
162 :
163 : # ifdef OPENSSL_FIPS
164 : if (FIPS_mode())
165 : return FIPS_ec_group_new_curve_gf2m(p, a, b, ctx);
166 : # endif
167 0 : meth = EC_GF2m_simple_method();
168 :
169 0 : ret = EC_GROUP_new(meth);
170 0 : if (ret == NULL)
171 : return NULL;
172 :
173 0 : if (!EC_GROUP_set_curve_GF2m(ret, p, a, b, ctx)) {
174 0 : EC_GROUP_clear_free(ret);
175 0 : return NULL;
176 : }
177 :
178 : return ret;
179 : }
180 : #endif
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