/*
 *
 * Copyright (c) 1998 Scott Oaks. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL purposes and
 * without fee is hereby granted.
 *
 * This sample source code is provided for example only,
 * on an unsupported, as-is basis. 
 *
 * AUTHOR MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. AUTHOR SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 *
 * THIS SOFTWARE IS NOT DESIGNED OR INTENDED FOR USE OR RESALE AS ON-LINE
 * CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS REQUIRING FAIL-SAFE
 * PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR FACILITIES, AIRCRAFT
 * NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL, DIRECT LIFE
 * SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH THE FAILURE OF THE
 * SOFTWARE COULD LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE
 * PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH RISK ACTIVITIES").  AUTHOR
 * SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR
 * HIGH RISK ACTIVITIES.
 */


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

public class Receive {
	public static void main(String args[]) {
		try {
			String data = null;
			byte signature[] = null;
			FileInputStream fis = new FileInputStream("test");
			ObjectInputStream ois = new ObjectInputStream(fis);
			Object o = ois.readObject();
			try {
			    data = (String) o;
			} catch (ClassCastException cce) {
			    System.out.println("Unexpected data in file");
			    System.exit(-1);
			}
			o = ois.readObject();
			try {
			    signature = (byte []) o;
			} catch (ClassCastException cce) {
			    System.out.println("Unexpected data in file");
			    System.exit(-1);
			}
			System.out.println("Received message");
			System.out.println(data);

			// In 1.2 beta 4, we need an argument to the getInstance method
			KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());
			ks.load(new FileInputStream(System.getProperty("user.home") + File.separator + ".keystore"), null);

			java.security.cert.Certificate c = ks.getCertificate(args[0]);
			PublicKey pk = c.getPublicKey();
			Signature s = Signature.getInstance("DSA");
			s.initVerify(pk);
			s.update(data.getBytes());
			if (s.verify(signature)) {
				System.out.println("Message is valid");
			}
			else System.out.println("Message was corrupted");
		} catch (Exception e) {
			System.out.println(e);
		}
	}
}