Android Open Source - TriPeaksSolitaireForAndroid Encryptor

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License

The source code is released under:

GNU General Public License

Java Source Code

/*
 * This file is a part of Tri Peaks Solitaire for Android
 *//w ww. j  a  v  a  2 s  .  c  o  m
 * Copyright (C) 2013-2014 by Valera Trubachev, Christian d'Heureuse, Todor 
 * Balabanov, Ina Baltadzhieva, Maria Barova, Kamelia Ivanova, Victor Vangelov, Daniela Pancheva
 *
 * Tri Peaks Solitaire for Android 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.
 *
 * Tri Peaks Solitaire for Android 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 
 * Tri Peaks Solitaire for Android.  If not, see <http://www.gnu.org/licenses/>.
 */

package eu.veldsoft.tri.peaks;

import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.KeySpec;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;

/**
 * a class used to encrypt and decrypt stuff
 * 
 * @author Valera Trubachev
 */
class Encryptor {
  /**
   * two cipher objects - one for encrypting and one for decrypting
   */
  Cipher encipher;

  /**
   * 
   */
  Cipher decipher;

  /**
   * salt for the encryption (more secure)
   */
  byte[] salt = { (byte) 0xA9, (byte) 0x9B, (byte) 0xC8, (byte) 0x32,
      (byte) 0x56, (byte) 0x35, (byte) 0xE3, (byte) 0x03 };

  /**
   * number of iterations for encryption
   */
  int iterCt = 19;

  /**
   * create the encryptor object
   * 
   * @param passPhrase
   */
  public Encryptor(String passPhrase) {
    /*
     * lots of things can go wrong
     */
    try {
      /*
       * create the PBE (Password-based ecryption) key specification
       */
      KeySpec keySpec = new PBEKeySpec(passPhrase.toCharArray(), salt,
          iterCt);

      /*
       * generate a secret encryption key (Password-Based Encryption with
       * Message Digest 5 and Data Encryption Standard)
       */
      SecretKey key = SecretKeyFactory.getInstance("PBEWithMD5AndDES")
          .generateSecret(keySpec);

      /*
       * create the Cipher objects
       */
      encipher = Cipher.getInstance(key.getAlgorithm());
      decipher = Cipher.getInstance(key.getAlgorithm());

      /*
       * create the encryption algorithm
       */
      AlgorithmParameterSpec pSpec = new PBEParameterSpec(salt, iterCt);

      /*
       * initialize the two Ciphers, with the same keya and algorithm, but
       * different modes
       */
      decipher.init(Cipher.DECRYPT_MODE, key, pSpec);
      encipher.init(Cipher.ENCRYPT_MODE, key, pSpec);

      /*
       * catch all the exceptions that can get thrown.
       */
    } catch (Exception e) {
    }
  }

  /**
   * encrypts a string
   * 
   * @param in
   * @return
   */
  public String encrypt(String in) {
    /*
     * lots of things that can go wrong
     */
    try {
      /*
       * Convert the string to UTF-8 bytecodes
       */
      byte[] utf8 = in.getBytes("UTF8");

      /*
       * have the Cipher encrypt the bytes
       */
      byte[] enBytes = encipher.doFinal(utf8);

      /*
       * Create a string from the bytes using Base64 encoding
       */
      String out = new String(Base64Coder.encode(enBytes));

      /*
       * return the encrypted string
       */
      return out;

      /*
       * catch all the exceptions
       */
    } catch (Exception e) {
    }

    /*
     * return null if there was an exception
     */
    return null;
  }

  /**
   * decrypts a string
   * 
   * @param in
   * @return
   */
  public String decrypt(String in) {
    /*
     * lots of things that can go wrong
     */
    try {
      /*
       * get the encrypted bytes by decoding the Base64-encoded text
       */
      byte[] deBytes = Base64Coder.decode(in);

      /*
       * use the Cipher to decrypt the bytes into UTF-8 bytecodes
       */
      byte[] utf8 = decipher.doFinal(deBytes);

      /*
       * create a new string from those bytes
       */
      String out = new String(utf8, "UTF8");

      /*
       * return the decrypted string
       */
      return out;

      /*
       * catch all the exceptions
       */
    } catch (Exception e) {
    }

    /*
     * return null if there was an exception
     */
    return null;
  }
}

Java Source Code List

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