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 static int dsa_builtin_keygen(DSA *dsa);
68
DSA_generate_key(DSA * dsa)69 int DSA_generate_key(DSA *dsa)
70 {
71 if(dsa->meth->dsa_keygen)
72 return dsa->meth->dsa_keygen(dsa);
73 return dsa_builtin_keygen(dsa);
74 }
75
dsa_builtin_keygen(DSA * dsa)76 static int dsa_builtin_keygen(DSA *dsa)
77 {
78 int ok=0;
79 BN_CTX *ctx=NULL;
80 BIGNUM *pub_key=NULL,*priv_key=NULL;
81
82 if ((ctx=BN_CTX_new()) == NULL) goto err;
83
84 if (dsa->priv_key == NULL)
85 {
86 if ((priv_key=BN_new()) == NULL) goto err;
87 }
88 else
89 priv_key=dsa->priv_key;
90
91 do
92 if (!BN_rand_range(priv_key,dsa->q)) goto err;
93 while (BN_is_zero(priv_key));
94
95 if (dsa->pub_key == NULL)
96 {
97 if ((pub_key=BN_new()) == NULL) goto err;
98 }
99 else
100 pub_key=dsa->pub_key;
101
102 {
103 BIGNUM local_prk;
104 BIGNUM *prk;
105
106 if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0)
107 {
108 BN_init(&local_prk);
109 prk = &local_prk;
110 BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME);
111 }
112 else
113 prk = priv_key;
114
115 if (!BN_mod_exp(pub_key,dsa->g,prk,dsa->p,ctx)) goto err;
116 }
117
118 dsa->priv_key=priv_key;
119 dsa->pub_key=pub_key;
120 ok=1;
121
122 err:
123 if ((pub_key != NULL) && (dsa->pub_key == NULL)) BN_free(pub_key);
124 if ((priv_key != NULL) && (dsa->priv_key == NULL)) BN_free(priv_key);
125 if (ctx != NULL) BN_CTX_free(ctx);
126 return(ok);
127 }
128 #endif
129