PasswordBasedEncryptor - jelszó alapú titkosítás, egyszerűen

Rengeteg kriptográfiai könyvtár, algoritmus, kutyafüle létezik. Ha pusztán arra van szükséged, hogy sok lacafaca nélkül enkriptálj és dekriptálj adatot egy általad megadott jelszó alapján, és nem szeretnél kilós könyvtáraktól függeni, akkor vess erre egy pillantást.

/*
 * Lithium Utilities
 * 
 * Copyright 2007-2011 Tibor Bősze <tibor.boesze@gmail.com>
 *
 * 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 hu.lithium.utils.crypto;


import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;

/**
 * Utility class for password based encryption of... well mostly other passwords.
 * 
 * @author tibi
 * @version 1.1
 */
public class PasswordBasedEncryptor {

	private static final String algo = "PBEWithMD5AndDES";
	private static final int iterations = 7;
	private static final byte[] salt = new byte[] { (byte) 0xCA, (byte) 0xFE, (byte) 0xBA, (byte) 0xBE, (byte) 0xDE,
			(byte) 0xAD, (byte) 0xBE, (byte) 0xEF };
	
	private final SecretKey secretKey;
	private final PBEParameterSpec params;

	public PasswordBasedEncryptor(char[] password) throws InvalidKeySpecException, NoSuchAlgorithmException {
		this(password, salt, iterations);
	}

	public PasswordBasedEncryptor(char[] password, byte[] salt, int iterations) throws InvalidKeySpecException,
			NoSuchAlgorithmException {
		params = new PBEParameterSpec(salt, iterations);
		PBEKeySpec ks = new PBEKeySpec(password);
		secretKey = SecretKeyFactory.getInstance(algo).generateSecret(ks);
		ks.clearPassword();
	}

	public byte[] encrypt(byte[] raw) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException,
			InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException {
		Cipher c = Cipher.getInstance(algo);
		c.init(Cipher.ENCRYPT_MODE, secretKey, params);
		return c.doFinal(raw);
	}

	public byte[] decrypt(byte[] enc) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException,
			InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException {
		Cipher c = Cipher.getInstance(algo);
		c.init(Cipher.DECRYPT_MODE, secretKey, params);
		return c.doFinal(enc);
	}

	public String encryptToBase64(byte[] raw) throws NoSuchAlgorithmException, NoSuchPaddingException,
			InvalidKeyException, InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException {
		return new String(Base64.encode(encrypt(raw)));
	}

	public byte[] decryptFromBase64(String encb64) throws NoSuchAlgorithmException, NoSuchPaddingException,
			InvalidKeyException, InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException {
		return decrypt(Base64.decode(encb64));
	}
	
	public static void main(String[] args) throws Exception {
		
		if (args.length != 3) {
			System.out.println("Usage: {encrypt|decrypt} <password> <data>");
			return;
		}
		
		boolean decrypt = "decrypt".equalsIgnoreCase(args[0]);
		String password = args[1]==null?"secret":args[1];
		String data = args[2]==null?"example":args[2];
		
		PasswordBasedEncryptor pbe = new PasswordBasedEncryptor(password.toCharArray());
		if (!decrypt) {
			System.out.println("encrypt(" + data + "): " + pbe.encryptToBase64(data.getBytes()));
		} else {
			System.out.println("decrypt(" + data + "): " + new String(pbe.decryptFromBase64(data)));
		}
	}

}