crypto/dsa/dsa_key.c

   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
  60
  61 #include <stdio.h>
  62 #include <time.h>
  63 #include "cryptlib.h"
  64 #ifndef OPENSSL_NO_SHA
  65 #include <openssl/bn.h>
  66 #include <openssl/dsa.h>
  67 #include <openssl/rand.h>
  68
  69 static int dsa_builtin_keygen(DSA *dsa);
  70
  71 int DSA_generate_key(DSA *dsa)
  72         {
  73         if(dsa->meth->dsa_keygen)
  74                 return dsa->meth->dsa_keygen(dsa);
  75         return dsa_builtin_keygen(dsa);
  76         }
  77
  78 static int dsa_builtin_keygen(DSA *dsa)
  79         {
  80         int ok=0;
  81         BN_CTX *ctx=NULL;
  82         BIGNUM *pub_key=NULL,*priv_key=NULL;
  83
  84         if ((ctx=BN_CTX_new()) == NULL) goto err;
  85
  86         if (dsa->priv_key == NULL)
  87                 {
  88                 if ((priv_key=BN_new()) == NULL) goto err;
  89                 }
  90         else
  91                 priv_key=dsa->priv_key;
  92
  93         do
  94                 if (!BN_rand_range(priv_key,dsa->q)) goto err;
  95         while (BN_is_zero(priv_key));
  96
  97         if (dsa->pub_key == NULL)
  98                 {
  99                 if ((pub_key=BN_new()) == NULL) goto err;
 100                 }
 101         else
 102                 pub_key=dsa->pub_key;
 103
 104         {
 105                 BIGNUM *local_prk = NULL;
 106                 BIGNUM *prk;
 107
 108                 if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0)
 109                         {
 110                         local_prk = prk = BN_new();
 111                         if(!local_prk) goto err;
 112                         BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME);
 113                         }
 114                 else
 115                         prk = priv_key;
 116
 117                 if (!BN_mod_exp(pub_key,dsa->g,prk,dsa->p,ctx))
 118                         {
 119                         if (local_prk != NULL) BN_free(local_prk);
 120                         goto err;
 121                         }
 122                 if (local_prk != NULL) BN_free(local_prk);
 123         }
 124
 125         dsa->priv_key=priv_key;
 126         dsa->pub_key=pub_key;
 127         ok=1;
 128
 129 err:
 130         if ((pub_key != NULL) && (dsa->pub_key == NULL)) BN_free(pub_key);
 131         if ((priv_key != NULL) && (dsa->priv_key == NULL)) BN_free(priv_key);
 132         if (ctx != NULL) BN_CTX_free(ctx);
 133         return(ok);
 134         }
 135 #endif