Java - Encrypt Decrypt, AES Encryption

library : commons-codec-1.8   https://www.dropbox.com/sh/qvoml3a8u34rl9x/LNFJFiWJky
atau :  https://www.dropbox.com/sh/qvoml3a8u34rl9x/LNFJFiWJky
 
/*
 * Author : Fandy Adam
 * Email  : casperadam91@gmail.com
 * netbeans 7.3.x JDK 1.7
 */
package encryptde;

import java.security.MessageDigest;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;

/**
 *
 * @author casper
 */
public class Encryption {

  private SecretKeySpec skeySpec;
  private Cipher cipher;
 
  public Encryption(byte [] keyraw) throws Exception{
    if(keyraw == null){
      byte[] bytesOfMessage = "".getBytes("UTF-8");
      MessageDigest md = MessageDigest.getInstance("MD5");
      byte[] bytes = md.digest(bytesOfMessage);
    
      skeySpec = new SecretKeySpec(bytes, "AES");
      cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
    }
    else{
  
    skeySpec = new SecretKeySpec(keyraw, "AES");
    cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
  
    }
  }
 
  public Encryption(String passphrase) throws Exception{
    byte[] bytesOfMessage = passphrase.getBytes("UTF-8");
    MessageDigest md = MessageDigest.getInstance("MD5");
    byte[] thedigest = md.digest(bytesOfMessage);
    skeySpec = new SecretKeySpec(thedigest, "AES");
  
  
    cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
  }
 
  public Encryption() throws Exception{
    byte[] bytesOfMessage = "".getBytes("UTF-8");
    MessageDigest md = MessageDigest.getInstance("MD5");
    byte[] thedigest = md.digest(bytesOfMessage);
    skeySpec = new SecretKeySpec(thedigest, "AES");
  
    skeySpec = new SecretKeySpec(new byte[16], "AES");
    cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
  }
 
  public byte[] encrypt (byte[] plaintext) throws Exception{
    //returns byte array encrypted with key
  
    cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
  
    byte[] ciphertext =  cipher.doFinal(plaintext);
  
    return ciphertext;
  }
 
  public byte[] decrypt (byte[] ciphertext) throws Exception{
    //returns byte array decrypted with key
    cipher.init(Cipher.DECRYPT_MODE, skeySpec);
  
    byte[] plaintext = cipher.doFinal(ciphertext);
  
    return plaintext;
  }
 
  public static void main(String[] args) throws Exception {

    String message="This is just an example";
    Encryption encrypter = new Encryption(new byte[16]);
  
    byte[] encrypted = encrypter.encrypt(message.getBytes("UTF-8"));
    byte[] decrypted = encrypter.decrypt(encrypted);
    System.out.println(new String (encrypted, "UTF-8"));
    System.out.println(new String (decrypted, "UTF-8"));

  }
}