import java.io.FileInputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.security.spec.*;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.KeySpec;
public final class TestePBE {
	private static SecretKey skey;
	private static final String algorithm = "AES/CBC/PKCS5Padding";
	public static final void encrypt(char[] password, File arq)
		throws  IOException, 
			BadPaddingException,
			NoSuchPaddingException,
			IllegalBlockSizeException,
			InvalidKeyException,
			NoSuchAlgorithmException {
        	SecretKeyFactory skf = SecretKeyFactory.getInstance(algorithm);
		KeySpec ks = new PBEKeySpec (password, new byte[]{1,2,3,4,5,6,7,8,9,10}, 1000);
		SecretKey skey = skf.generateSecret (ks);
		final Cipher cipher = Cipher.getInstance(algorithm);
		cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
		return cipher.doFinal(text.getBytes());
	}
	public static final void decrypt(char[] password, File arq)
		throws  IOException,
			BadPaddingException,
			NoSuchPaddingException,
			IllegalBlockSizeException,
			InvalidKeyException,
			NoSuchAlgorithmException {
		SecretKeyFactory skf = SecretKeyFactory.getInstance(algorithm);
		KeySpec ks = new PBEKeySpec (password, new byte[]{1,2,3,4,5,6,7,8,9,10}, 1000);
		SecretKey skey = skf.generateSecret (ks);
		final Cipher cipher = Cipher.getInstance(algorithm);
		cipher.init(Cipher.DECRYPT_MODE, skeySpec);
		return cipher.doFinal(text.getBytes());
	}
	private static int tamArquivoTeste = 12345;
	private static void geraArquivoTeste(File arq) throws IOException {
	    Random r = new Random ();
	    r.setSeed (123456789);
	    byte[] bytes = new byte[tamArquivoTeste];
	    r.next (bytes);
	    OutputStream os = new FileOutputStream (arq);
	    os.write (bytes);
	    os.close();
        }
	private static boolean confereArquivoTeste(File arq) throws IOException {
	    boolean ret = true;
	    Random r = new Random ();
	    r.setSeed (123456789);
	    byte[] bytes = new byte[tamArquivoTeste];
	    r.next (bytes);
	    byte[] readBytes = new byte[tamArquivoTeste];
	    if (arq.length() != tamArquivoTeste) {
	        System.out.println ("Arquivo de tamanho diferente do esperado");
	        return false;
            }
	    InputStream is = new FileInputStream (arq);
	    int nBytes = is.read (readBytes);
	    is.close();
	    if (nBytes != tamArquivoTeste) {
	        System.out.println ("Arquivo de tamanho diferente do esperado");
	        return false;
            }
            return Arrays.equals (readBytes, bytes);
        }
	public static void main(String[] args) throws Exception {
            String password = "senha altamente secreta";
            File arqEntrada = new File ("teste.bin");
            File arqCifrado = new File ("teste.bin.cifrado");
            File arqDecifrado = new File ("teste.bin.decifrado");
            geraArquivoTeste (arqTeste);		
            TestePBE.encrypt (password, arqEntrada, arqCifrado);
            //-- Checando com a senha certa
            TestePBE.decrypt (password, arqCifrado, arqDecifrado);
            if (confereArquivoTeste (arqEntrada, arqDecifrado)) {
                System.out.println ("Os arquivos bateram");
            }
            //-- Checando com a senha errada
            TestePBE.decrypt ("senhaErrada", arqTeste);
            if (confereArquivoTeste (arqEntrada, arqDecifrado)) {
                System.out.println ("Os arquivos bateram");
            }
	}
}