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generate_elgamal_key.cc

/*
 * Copyright 2003 Michael A. Marsh, Cornell University. All rights reserved.
 * This software is released under the modified BSD license.
 * See the file LICENSE in the top-level directory for details.
 */
//
// $Id: generate_elgamal_key.cc,v 1.4 2004/05/19 15:56:46 mmarsh Exp $
//
// $Log: generate_elgamal_key.cc,v $
// Revision 1.4  2004/05/19 15:56:46  mmarsh
// *** empty log message ***
//
// Revision 1.3  2003/11/06 18:11:51  mmarsh
// Cleaned up doxygen page label and title.
//
// Revision 1.2  2003/11/04 22:07:35  mmarsh
// General code cleanup and reorganization.
//
//

#include <fstream>

#include <openssl/pem.h>
#include <openssl/ssl.h>

#include "CODEX_Ciphers/RSA.h"
#include "CODEX_Ciphers/ElGamal.h"
#include "CODEX_Ciphers/SHA1HashFunction.h"
#include "CODEX_Client/Message.h"

int main()
{
   SSLeay_add_ssl_algorithms();
   CODEX_Ciphers::RSAPrivateKey privKey;
   // use cmdline switch
   privKey.fromPEMFile( "/users/mmarsh/src/CODEX/scripts/service.private.pem",
                         0 );
   // use cmdline switch
   CODEX_Ciphers::ElGamalKeyPairGenerator gen(1024);
   CODEX_Ciphers::ElGamalPublicKey* pubEGKey = 0;
   CODEX_Ciphers::ElGamalPrivateKey* privEGKey = 0;
   cout << "generating ElGamal key pair (may take awhile)..." << flush;
   gen(pubEGKey,privEGKey);
   cout << "done" << endl;
   BIGNUM * h = BN_new();
   BIGNUM * temp = BN_new();
   BN_CTX * ctx = BN_CTX_new();
   BIGNUM * q = (BIGNUM*)pubEGKey->q();
   BIGNUM * p = (BIGNUM*)pubEGKey->p().value();
   bool flag;
   cout << "generating auxiliary generator..." << flush;
   do
   {
      flag = false;
      BN_rand_range(h,p);
      if ( 0 >= BN_cmp(h,BN_value_one()) )
      {
         flag = true;
      }
      else
      {
         BN_mod_mul(temp,h,h,p,ctx);
         if ( 0 == BN_cmp( temp, BN_value_one() ) )
         {
            flag = true;
         }
         else
         {
            BN_mod_exp(temp,h,q,p,ctx);
            if ( 0 == BN_cmp( temp, BN_value_one() ) )
            {
               flag = true;
            }
         }
      }
   } while ( flag );
   cout << "done" << endl;
   BN_free(temp);
   CODEX_Server::AugmentedEGPublicKey pkMsg( *pubEGKey,
                                             CODEX_ASN1::BigNumber(h) );
   CODEX_Ciphers::SHA1HashFunction hashFunc;
   BIGNUM * digest = pkMsg.digest( hashFunc );
   CODEX_Ciphers::RSASignature* signature = privKey.sign( digest );
   BN_free( digest );
   CODEX_Server::SignedAugmentedEGPublicKey signedPKMsg( pkMsg, *signature );
   delete signature;
   privEGKey->toFile("/users/mmarsh/src/CODEX/elgamal.priv");
   int length = signedPKMsg.marshal(0);
   unsigned char* buff = new unsigned char[length];
   unsigned char* pBuff = buff;
   signedPKMsg.marshal(&pBuff);
   ofstream os("/users/mmarsh/src/CODEX/elgamal.pub");
   for ( int i = 0 ; i < length ; ++i )
   {
      os << buff[i];
   }
   os.close();
   delete [] buff;
   return 0;
}

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