/*
//
// GetKeys.java
//
// Generate and display private and public keys.
//
*/

import java.security.*;
import java.io.*;

public class GetKeys {

 public static void main(String arg[]) {
            
  try {

  // Convert argument to integer
  // Default modulus to 512 if no argument given

  int modArg = 512;

  if (arg.length != 0) 
   modArg = Integer.parseInt(arg[0]);
   
  // Get key generator

  KeyPairGenerator kg = KeyPairGenerator.getInstance("DSA");
  SecureRandom rand = SecureRandom.getInstance("SHA1PRNG");
  kg.initialize(modArg, rand);

  // Get key private/public key pair

  KeyPair kp = kg.generateKeyPair();
  PrivateKey prv = kp.getPrivate();
  PublicKey pub = kp.getPublic();

  // Print private/public keys to stdout

  System.out.println("Public key: " + pub);
  System.out.println("Private key: " + prv);


  }

  catch (Exception err) {
   System.err.println(err);
   System.err.println("Usage: java GetKeys [modArg]");
  }
 }
}