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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 
EC_GROUP_new_curve_GFp(const BIGNUM * p,const BIGNUM * a,const BIGNUM * b,BN_CTX * ctx)76 EC_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 	meth = EC_GFp_nist_method();
82 
83 	ret = EC_GROUP_new(meth);
84 	if (ret == NULL)
85 		return NULL;
86 
87 	if (!EC_GROUP_set_curve_GFp(ret, p, a, b, ctx))
88 		{
89 		unsigned long err;
90 
91 		err = ERR_peek_last_error();
92 
93 		if (!(ERR_GET_LIB(err) == ERR_LIB_EC &&
94 			((ERR_GET_REASON(err) == EC_R_NOT_A_NIST_PRIME) ||
95 			 (ERR_GET_REASON(err) == EC_R_NOT_A_SUPPORTED_NIST_PRIME))))
96 			{
97 			/* real error */
98 
99 			EC_GROUP_clear_free(ret);
100 			return NULL;
101 			}
102 
103 
104 		/* not an actual error, we just cannot use EC_GFp_nist_method */
105 
106 		ERR_clear_error();
107 
108 		EC_GROUP_clear_free(ret);
109 		meth = EC_GFp_mont_method();
110 
111 		ret = EC_GROUP_new(meth);
112 		if (ret == NULL)
113 			return NULL;
114 
115 		if (!EC_GROUP_set_curve_GFp(ret, p, a, b, ctx))
116 			{
117 			EC_GROUP_clear_free(ret);
118 			return NULL;
119 			}
120 		}
121 
122 	return ret;
123 	}
124 
125 
EC_GROUP_new_curve_GF2m(const BIGNUM * p,const BIGNUM * a,const BIGNUM * b,BN_CTX * ctx)126 EC_GROUP *EC_GROUP_new_curve_GF2m(const BIGNUM *p, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
127 	{
128 	const EC_METHOD *meth;
129 	EC_GROUP *ret;
130 
131 	meth = EC_GF2m_simple_method();
132 
133 	ret = EC_GROUP_new(meth);
134 	if (ret == NULL)
135 		return NULL;
136 
137 	if (!EC_GROUP_set_curve_GF2m(ret, p, a, b, ctx))
138 		{
139 		EC_GROUP_clear_free(ret);
140 		return NULL;
141 		}
142 
143 	return ret;
144 	}
145