AgreementFinaliser.java

/**
 * Copyright (c) 2011, SOCIETIES Consortium (WATERFORD INSTITUTE OF TECHNOLOGY (TSSG), HERIOT-WATT UNIVERSITY (HWU), SOLUTA.NET 
 * (SN), GERMAN AEROSPACE CENTRE (Deutsches Zentrum fuer Luft- und Raumfahrt e.V.) (DLR), Zavod za varnostne tehnologije
 * informacijske družbe in elektronsko poslovanje (SETCCE), INSTITUTE OF COMMUNICATION AND COMPUTER SYSTEMS (ICCS), LAKE
 * COMMUNICATIONS (LAKE), INTEL PERFORMANCE LEARNING SOLUTIONS LTD (INTEL), PORTUGAL TELECOM INOVAÇÃO, SA (PTIN), IBM Corp., 
 * INSTITUT TELECOM (ITSUD), AMITEC DIACHYTI EFYIA PLIROFORIKI KAI EPIKINONIES ETERIA PERIORISMENIS EFTHINIS (AMITEC), TELECOM 
 * ITALIA S.p.a.(TI),  TRIALOG (TRIALOG), Stiftelsen SINTEF (SINTEF), NEC EUROPE LTD (NEC))
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following
 * conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
 *    disclaimer in the documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
 * SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.societies.privacytrust.privacyprotection.privacynegotiation.negotiation.client;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.SecureRandom;
import java.security.Signature;
import java.security.SignatureException;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.societies.api.internal.schema.privacytrust.privacyprotection.model.privacypolicy.Agreement;


/**
 * @author Elizabeth
 *
 */
public class AgreementFinaliser {

	private KeyPair keypair;
	private Logger logging = LoggerFactory.getLogger(this.getClass());

	public AgreementFinaliser(){

	}

	public byte[] signAgreement(Agreement agreement){

		this.generateKeys();
		if (keypair==null){
			log("Unable to generate Keys for signing the Agreement object");
			return null;
		}

		try {
			Signature dsa = Signature.getInstance("SHA1withDSA");
			dsa.initSign(this.keypair.getPrivate());
			byte[] byteArray = this.getBytes(agreement);

			dsa.update(byteArray);
			return dsa.sign();
		}
		catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		catch (SignatureException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		catch (InvalidKeyException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}	
		catch (NoSuchAlgorithmException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		return null;
	}

	private byte[] getBytes(Object obj) throws java.io.IOException{
		ByteArrayOutputStream bos = new ByteArrayOutputStream(); 
		ObjectOutputStream oos = new ObjectOutputStream(bos); 
		oos.writeObject(obj);
		oos.flush(); 
		oos.close(); 
		bos.close();
		byte [] data = bos.toByteArray();
		return data;
	}


	private void generateKeys(){
		try {
			KeyPairGenerator kpg = KeyPairGenerator.getInstance("DSA");

			SecureRandom random = SecureRandom.getInstance("SHA1PRNG", "SUN");
			kpg.initialize(1024,random);
			this.keypair = kpg.generateKeyPair();

		} 
		catch (NoSuchProviderException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}	
		catch (NoSuchAlgorithmException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}
	
	public Key getPublicKey(){
		return this.keypair.getPublic();
	}
	
	private void log(String message){
		this.logging.info(this.getClass().getName()+" : "+message);
	}

}