Serviços criptográficos

import javax.crypto.Cipher;

import javax.crypto.KeyGenerator;

import javax.crypto.NoSuchPaddingException;

import javax.crypto.IllegalBlockSizeException;

import javax.crypto.BadPaddingException;

import java.security.Key;

import java.security.Security;

import java.security.NoSuchAlgorithmException;

import java.security.InvalidKeyException;

public class DESCryptoTest

{

public static void main(String[] args)

{

Security.addProvider(new com.sun.crypto.provider.SunJCE());

try
    {
        //DES é apenas um dos vários algorítmos de criptografia
        //que podem ser utilizados
        KeyGenerator kg = KeyGenerator.getInstance("DES");
        Key key = kg.generateKey();
        Cipher cipher = Cipher.getInstance("DES");

        //A String original
        byte[] data = "Hello World!".getBytes();
        System.out.println("Original data : " + new String(data));

        //A criptografia
        cipher.init(Cipher.ENCRYPT_MODE, key);
        byte[] result = cipher.doFinal(data);
        System.out.println("Encrypted data: " + new String(result));

        //A decriptografia
        cipher.init(Cipher.DECRYPT_MODE, key);
        byte[] original = cipher.doFinal(result);
        System.out.println("Decrypted data: " + new String(original));
    }
    catch (NoSuchAlgorithmException e)
    {
        e.printStackTrace();
    }
    catch (NoSuchPaddingException e)
    {
        e.printStackTrace();
    }
    catch (InvalidKeyException e)
    {
        e.printStackTrace();
    }
    catch (IllegalStateException e)
    {
        e.printStackTrace();
    }
    catch (IllegalBlockSizeException e)
    {
        e.printStackTrace();
    }
    catch (BadPaddingException e)
    {
        e.printStackTrace();
    }
}