1 /* crypto/dsa/dsa_key.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to. The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 * must display the following acknowledgement:
33 * "This product includes cryptographic software written by
34 * Eric Young (eay@cryptsoft.com)"
35 * The word 'cryptographic' can be left out if the rouines from the library
36 * being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 * the apps directory (application code) you must include an acknowledgement:
39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed. i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58
59 #include <stdio.h>
60 #include <time.h>
61 #include "cryptlib.h"
62 #ifndef OPENSSL_NO_SHA
63 #include <openssl/bn.h>
64 #include <openssl/dsa.h>
65 #include <openssl/rand.h>
66
67 #ifdef OPENSSL_FIPS
68 #include <openssl/fips.h>
69 #endif
70
71 static int dsa_builtin_keygen(DSA *dsa);
72
73 int DSA_generate_key(DSA *dsa)
74 {
75 #ifdef OPENSSL_FIPS
76 if (FIPS_mode() && !(dsa->meth->flags & DSA_FLAG_FIPS_METHOD)
77 && !(dsa->flags & DSA_FLAG_NON_FIPS_ALLOW))
78 {
79 DSAerr(DSA_F_DSA_GENERATE_KEY, DSA_R_NON_FIPS_DSA_METHOD);
80 return 0;
81 }
82 #endif
83 if(dsa->meth->dsa_keygen)
84 return dsa->meth->dsa_keygen(dsa);
85 #ifdef OPENSSL_FIPS
86 if (FIPS_mode())
87 return FIPS_dsa_generate_key(dsa);
88 #endif
89 return dsa_builtin_keygen(dsa);
90 }
91
92 static int dsa_builtin_keygen(DSA *dsa)
93 {
94 int ok=0;
95 BN_CTX *ctx=NULL;
96 BIGNUM *pub_key=NULL,*priv_key=NULL;
97
98 if ((ctx=BN_CTX_new()) == NULL) goto err;
99
100 if (dsa->priv_key == NULL)
101 {
102 if ((priv_key=BN_new()) == NULL) goto err;
103 }
104 else
105 priv_key=dsa->priv_key;
106
107 do
108 if (!BN_rand_range(priv_key,dsa->q)) goto err;
109 while (BN_is_zero(priv_key));
110
111 if (dsa->pub_key == NULL)
112 {
113 if ((pub_key=BN_new()) == NULL) goto err;
114 }
115 else
116 pub_key=dsa->pub_key;
117
118 {
119 BIGNUM local_prk;
120 BIGNUM *prk;
121
122 if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0)
123 {
124 BN_init(&local_prk);
125 prk = &local_prk;
126 BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME);
127 }
128 else
129 prk = priv_key;
130
131 if (!BN_mod_exp(pub_key,dsa->g,prk,dsa->p,ctx)) goto err;
132 }
133
134 dsa->priv_key=priv_key;
135 dsa->pub_key=pub_key;
136 ok=1;
137
138 err:
139 if ((pub_key != NULL) && (dsa->pub_key == NULL)) BN_free(pub_key);
140 if ((priv_key != NULL) && (dsa->priv_key == NULL)) BN_free(priv_key);
141 if (ctx != NULL) BN_CTX_free(ctx);
142 return(ok);
143 }
144 #endif