Android Open Source - CipherChat Utilities

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Back to project page CipherChat.
License

The source code is released under:
MIT License
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Java Source Code

package com.desperate.common;
//from  ww  w  .  jav  a2  s .  c  o m
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.io.UnsupportedEncodingException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

import javax.crypto.Cipher;
import javax.crypto.CipherOutputStream;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class Utilities {

  public static final long tolerance = 10 * 60 * 1000; // 10 minutes DEBUG
  public static final String charset = "ISO-8859-1";
  public static final String cipherAlgorithm = "AES";
  public static final String cipherMode = "AES/CBC/PKCS5Padding";
  public static final int keySize = 128;

  /**
   * This class cannot be instantiated.
   */
  private Utilities() {
  }

  /**
   * Ciphers a serializable object using {@value #cipherMode}.
   * 
   * @param obj
   *            Object to be serialized
   * @param key
   *            Key to be used
   * @return
   * @throws NoSuchAlgorithmException
   * @throws NoSuchPaddingException
   * @throws InvalidKeyException
   * @throws InvalidAlgorithmParameterException
   * @throws IOException
   * 
   * @see #decipherObject(Serializable, SecretKeySpec)
   */
  public static byte[] cipherObject(Serializable obj, SecretKeySpec key) throws NoSuchAlgorithmException, NoSuchPaddingException,
      InvalidKeyException, InvalidAlgorithmParameterException, IOException {

    // Prepare AES cipher
    Cipher aes = Cipher.getInstance(Utilities.cipherMode);
    aes.init(Cipher.ENCRYPT_MODE, key, new IvParameterSpec(new byte[aes.getBlockSize()]));

    // Prepare streams
    ObjectOutputStream oos;
    ByteArrayOutputStream plainBaos;
    CipherOutputStream cos;
    ByteArrayOutputStream cipherBaos;

    // Write object to the oos -> to the plainBaos
    plainBaos = new ByteArrayOutputStream();
    oos = new ObjectOutputStream(plainBaos);

    oos.writeObject(obj);
    oos.flush();
    oos.close();

    byte[] plainText = plainBaos.toByteArray();

    // Write it to cipherStream, which ciphers it
    cipherBaos = new ByteArrayOutputStream();
    cos = new CipherOutputStream(cipherBaos, aes);

    cos.write(plainText);
    cos.flush();
    cos.close();

    // Get ciphered output
    byte[] cipherText = cipherBaos.toByteArray();

    cipherBaos.flush();
    cipherBaos.close();

    return cipherText;
  }

  /**
   * Deciphers an array of bytes into an object.
   * 
   * @param cipherText
   * @param key
   *            Key to be used.
   * @return
   * @throws NoSuchAlgorithmException
   * @throws NoSuchPaddingException
   * @throws InvalidKeyException
   * @throws InvalidAlgorithmParameterException
   * @throws IOException
   * @throws ClassNotFoundException
   * 
   * @see #cipherObject(Serializable, SecretKeySpec)
   */
  public static Serializable decipherObject(byte[] cipherText, SecretKeySpec key) throws NoSuchAlgorithmException, NoSuchPaddingException,
      InvalidKeyException, InvalidAlgorithmParameterException, IOException, ClassNotFoundException {

    // Prepare AES cipher
    Cipher aes = Cipher.getInstance(Utilities.cipherMode);
    aes.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(new byte[aes.getBlockSize()]));

    // Prepare streams
    CipherOutputStream cos;
    ByteArrayOutputStream decipherBaos;
    ObjectInputStream ois;
    ByteArrayInputStream plainBais;

    // Write it to cipherStream, which ciphers it
    decipherBaos = new ByteArrayOutputStream();
    cos = new CipherOutputStream(decipherBaos, aes);

    cos.write(cipherText);
    cos.flush();
    decipherBaos.flush();
    cos.close();

    // Get deciphered output
    byte[] plainText = decipherBaos.toByteArray();
    decipherBaos.close();

    // Write bytes to the plainBais -> to the object deserialize stream
    plainBais = new ByteArrayInputStream(plainText);
    ois = new ObjectInputStream(plainBais);

    Serializable obj = (Serializable) ois.readObject();

    return obj;
  }

  public static String keyToString(SecretKeySpec key) {
    try {
      return new String(key.getEncoded(), Utilities.charset);
    } catch (UnsupportedEncodingException e) {
      throw new RuntimeException(e);
    }
  }

}
Java Source Code List
