/** 
Password based encryption with AES, this program is derived by A. Lisitsa  from the code by mrclay 
taken from 
https://github.com/mrclay/jSecureEdit/tree/master/src/org/mrclay/crypto 

Notice that it **works only for the key size 128** see  the line 

> KeySpec spec = new PBEKeySpec(password, salt, 1024, 128);

below. 
For other AES key sizes (192,256) it does not work, producing the exception: Illegal key size or default parameters.  

**/
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.InvalidParameterSpecException;
import java.security.spec.KeySpec;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.security.Key;

import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import javax.crypto.spec.PBEParameterSpec;
import javax.crypto.spec.SecretKeySpec;


public class PBE {
     public static void main(
        String[]    args)
        throws Exception 
    {   
        char[]  password = "newpassword".toCharArray();
         byte[] salt = { (byte)0xc7, (byte)0x73, (byte)0x21, 
                      (byte)0x8c, (byte)0x7e, (byte)0xc8, (byte)0xee, (byte)0x99 };
        SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
        KeySpec spec = new PBEKeySpec(password, salt, 1024, 128);
        Key secretKey = new SecretKeySpec(factory.generateSecret(spec).getEncoded(), "AES");
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);
        byte[]  cleartext = "This is another example".getBytes(); 
        byte[]  ciphertext = cipher.doFinal(cleartext); 
        System.out.println("cipher : " + Utils.toHex(ciphertext));
    }

}