AESEncrypterJCA.java

/*
 * Copyright 2011 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package de.idyl.winzipaes.impl;

import java.security.SecureRandom;
import java.util.Random;

/**
 * Encrypter adapter for the Java Cryptography Architecture.
 *
 * @author Matthew Dempsky <mdempsky@google.com>
 */
public class AESEncrypterJCA implements AESEncrypter {

	private byte[] salt;
	private AESUtilsJCA utils;

	public void init(String password, int keySize) {
		salt = createSalt(keySize / 16);
		utils = new AESUtilsJCA(password, keySize, salt);
	}

	@Override
	public void encrypt(byte[] in, int length) {
		utils.cryptUpdate(in, length);
		utils.authUpdate(in, length);
	}

	@Override
	public byte[] getSalt() {
		return salt;
	}

	@Override
	public byte[] getPwVerification() {
		return utils.getPasswordVerifier();
	}

	@Override
	public byte[] getFinalAuthentication() {
		return utils.getFinalAuthentifier();
	}

	private static final Random RANDOM = new SecureRandom();

	private static byte[] createSalt(int size) {
		byte[] salt = new byte[size];
		RANDOM.nextBytes(salt);
		return salt;
	}

}