/**
 * The MIT License (MIT)
 * 
 * Copyright (c) 2013 tojo
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
package com.github.tojo.session.cookies;

import java.io.UnsupportedEncodingException;
import java.util.UUID;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.lang.ArrayUtils;

/**
 * Default implementation of {@link SessionInACookie}.
 * 
 * @author github.com/tojo
 */
public class SessionInACookieDefaultImpl extends SessionInACookie {

	private static final int SESSION_ID_LENGTH = 36;

	// TODO Transformer strategies

	/**
	 * Constructor
	 * 
	 * @param secret
	 *            shared secret for en-/decryption
	 * @param iv
	 *            initial vector for en-/decryption
	 * @param cipherStrategy
	 * @param signatureStrategy
	 * @param timeoutStrategy
	 * @param blacklistStrategy
	 */
	public SessionInACookieDefaultImpl(CipherStrategy cipherStrategy,
			SignatureStrategy signatureStrategy,
			TimeoutStrategy timeoutStrategy, BlacklistStrategy blacklistStrategy) {
		super(cipherStrategy, signatureStrategy, timeoutStrategy,
				blacklistStrategy);
	}

	@Override
	public CookieValue encode(SessionData sessionData)
			throws CipherStrategyException {
		try {
			// 1. create session id
			byte[] sessionId = UUID.randomUUID().toString().getBytes("UTF-8");

			// 2. prefix session data with the session id
			byte[] dataWithSessionId = ArrayUtils.addAll(sessionId,
					sessionData.asBytes());

			// 3. calculate the cookie value
			CookieValue cookieValue = encryptSignAndEncode(dataWithSessionId);

			// 4. hit timeout strategy
			timeoutStrategy.issue(sessionData, cookieValue);

			return cookieValue;
		} catch (UnsupportedEncodingException e) {
			throw new RuntimeException(e);
		}
	}

	@Override
	public byte[] decode(CookieValue cookieValue) throws TimeoutException,
			SignatureException, BlacklistException {

		// 1. check blacklist
		blacklistStrategy.check(cookieValue);

		// 2. advance session timeout
		timeoutStrategy.advance(cookieValue);

		// 3. decode
		byte[] dataWithSessionId;
		dataWithSessionId = decodeDecryptAndVerifySignature(cookieValue
				.asBytes());

		// 4. extract the session id
		byte[] sessionId = ArrayUtils.subarray(dataWithSessionId, 0,
				SESSION_ID_LENGTH);

		// 5. extract the session data
		byte[] sessionData = ArrayUtils.subarray(dataWithSessionId,
				SESSION_ID_LENGTH, dataWithSessionId.length);

		// 3. return the session data
		return sessionData;
	}

	// /////////////////////////////////////////////////
	// non-public API
	// /////////////////////////////////////////////////

	CookieValue encryptSignAndEncode(byte[] sessionData)
			throws CipherStrategyException {
		assertNotNullAndEmpty(sessionData);

		// 1. encrypt
		byte[] encryptedSessionData = cipherStrategy.encipher(sessionData);

		// 2. sign
		byte[] signedSessionData = signatureStrategy.sign(encryptedSessionData);

		// 3. decode
		byte[] cookieValue = Base64.encodeBase64(signedSessionData);

		// return the encrypted, signed and base64 encoded session data as
		// cookie value
		return new CookieValue(cookieValue);
	}

	byte[] decodeDecryptAndVerifySignature(byte[] cookieValue)
			throws SignatureException {
		assertNotNullAndEmpty(cookieValue);

		// 1. decode
		byte[] encryptedAndSignedSessionData = Base64.decodeBase64(cookieValue);

		// 2. validate signature
		byte[] encryptedSessionData = signatureStrategy
				.validate(encryptedAndSignedSessionData);

		// 3. encrypt
		byte[] sessionData = cipherStrategy.decipher(encryptedSessionData);

		// return the decoded, decrypted and validated cookie value as session
		// data
		return sessionData;
	}
}
@@ -2248,32 +2248,116 @@
 eate session id%0A
+%09%09%09// is this as secure as using SecureRandom? if not sure, better use SecureRandom%0A
 %09%09%09byte%5B%5D sessio
@@ -4748,8 +4748,9 @@
 ta;%0A%09%7D%0A%7D
+%0A

Update SessionInACookieDefaultImpl.java