gsn.http.ac.Protector.java Source code

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Here is the source code for gsn.http.ac.Protector.java

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/**
* Global Sensor Networks (GSN) Source Code
* Copyright (c) 2006-2014, Ecole Polytechnique Federale de Lausanne (EPFL)
* 
* This file is part of GSN.
* 
* GSN is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
* 
* GSN is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
* 
* You should have received a copy of the GNU General Public License
* along with GSN.  If not, see <http://www.gnu.org/licenses/>.
* 
* File: src/gsn/http/ac/Protector.java
*
* @author Behnaz Bostanipour
* @author Julien Eberle
*
*/

package gsn.http.ac;

/**
 * Created by IntelliJ IDEA.
 * User: Behnaz Bostanipour
 * Date: Apr 14, 2010
 * Time: 4:39:13 PM
 * To change this template use File | Settings | File Templates.
 */
import java.security.*;

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;

import org.slf4j.LoggerFactory;
import org.slf4j.Logger;
import org.apache.commons.codec.binary.*;

/* This class helps to encrypt user passwords using AES encryption algo, we use a salt for a more robust encryption, salt is stored in a property file "acuserpassword.properties"*/
public class Protector {
    private static transient Logger logger = LoggerFactory.getLogger(Protector.class);

    private static final String ALGORITHM = "AES";
    private static final int ITERATIONS = 2;
    private static final String DEFAULT_SALT = "this is a simple clear salt";

    private static final byte[] keyValue = new byte[] { 'T', 'h', 'i', 's', 'I', 's', 'A', 'S', 'e', 'c', 'r', 'e',
            't', 'K', 'e', 'y' };

    public static String encrypt(String value) throws Exception {
        logger.debug("Encrypt key");
        Key key = generateKey();
        String salt = getSalt();
        Cipher c = Cipher.getInstance(ALGORITHM);
        c.init(Cipher.ENCRYPT_MODE, key);

        String valueToEnc = null;
        String eValue = value;
        for (int i = 0; i < ITERATIONS; i++) {
            valueToEnc = salt + eValue;
            byte[] encValue = c.doFinal(valueToEnc.getBytes());
            eValue = new sun.misc.BASE64Encoder().encode(encValue);
            //eValue = Base64.encodeBase64String(encValue);
        }
        return eValue;
    }

    public static String decrypt(String value) throws Exception {
        Key key = generateKey();
        String salt = getSalt();
        Cipher c = Cipher.getInstance(ALGORITHM);
        c.init(Cipher.DECRYPT_MODE, key);

        String dValue = null;
        String valueToDecrypt = value;
        for (int i = 0; i < ITERATIONS; i++) {
            byte[] decordedValue = new sun.misc.BASE64Decoder().decodeBuffer(valueToDecrypt);
            //byte[] decordedValue = Base64.decodeBase64(valueToDecrypt);
            byte[] decValue = c.doFinal(decordedValue);
            dValue = new String(decValue).substring(salt.length());
            valueToDecrypt = dValue;
        }
        return dValue;
    }

    private static Key generateKey() throws Exception {
        Key key = new SecretKeySpec(keyValue, ALGORITHM);
        return key;
    }

    private static String getSalt() {
        String s = System.getProperty("salt");
        if (s == null)
            return DEFAULT_SALT;
        else
            return s;
    }
}