/* from http://www.linuxjournal.com/article.php?sid=6131 */
   /* run `bc < DiffieHellmanWithDB.txt` */

   q = 563      /* Alice and Bob select a large prime */
   a = 5      /* ...and another random number       */
   xa = 9      /* Alice picks the random number 9 */
   xb = 14      /* Bob picks the random number 14 */
   
   ya = a ^ xa   /* Alice */
   ya = ya % q
   print "\nAlice sends ya = ", ya," to Bob\n";
   
   yb = a ^ xb   /* Bob */
   yb = yb % q
   print "Bob sends yb = ", yb," to Alice\n";
   
   ka = yb ^ xa
   print "\n   from yb^xa = ";ka;
   ka = ka % q
   print "         Alice calculates ka = ",ka,"\n"
   
   kb = ya ^ xb
   print "   from ya^xb = "; kb;
   kb = kb % q
   print "         Bob calculates kb = ",kb,"\n";
   print "\nThey can now use ",kb," to encrypt messages.\n";
   quit