armenak / DataDefender

 * Copyright 2014-2021, Armenak Grigoryan, and individual contributors as indicated

 * by the @authors tag. See the copyright.txt in the distribution for a

 * full listing of individual contributors.

 *

 * This is free software; you can redistribute it and/or modify it

 * under the terms of the GNU Lesser General Public License as

 * published by the Free Software Foundation; either version 2.1 of

 * the License, or (at your option) any later version.

 *

 * This software 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

 * Lesser General Public License for more details.

 */

package com.strider.datadefender.utils;

import java.io.UnsupportedEncodingException;

import java.security.InvalidKeyException;

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

import java.util.Arrays;

import java.util.Base64;

import javax.crypto.BadPaddingException;

import javax.crypto.Cipher;

import javax.crypto.IllegalBlockSizeException;

import javax.crypto.NoSuchPaddingException;

import javax.crypto.spec.SecretKeySpec;

import lombok.extern.log4j.Log4j2;

/**

 * This class implements determenistic data anonymization 

 * by encoding the data using "salt" and decoding it.

 * 

 * @author Armenak Grigoryan

 */

@Log4j2

public final class Encoder {

    private static SecretKeySpec secretKey;

    private static byte[] key;

    /**

     * Empty constructor 

     */

    public Encoder() {

    }

    public static void setKey(String myKey) {

        MessageDigest sha = null;

        try {

            key = myKey.getBytes("UTF-8");

            sha = MessageDigest.getInstance("SHA-1");

            key = sha.digest(key);

            key = Arrays.copyOf(key, 16); 

            secretKey = new SecretKeySpec(key, "AES");

        } 

        catch (NoSuchAlgorithmException | UnsupportedEncodingException e) {

            log.debug(e);

        }

    }    

    }        

    public String decrypt(String strToDecrypt, String secret) {

        try {

            setKey(secret);

            Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5PADDING");

            cipher.init(Cipher.DECRYPT_MODE, secretKey);

            return new String(cipher.doFinal(Base64.getDecoder().decode(strToDecrypt)));

        } catch (InvalidKeyException | NoSuchAlgorithmException | BadPaddingException | 

                 IllegalBlockSizeException | NoSuchPaddingException e) {

            log.error("Error while decrypting: " + e.toString());

        }

        return null;

    }

}