Encrypted Preferences in Java

Listing 3: A simple test program, this time using encryption. It does more or less the same thing as the program in Listing 1, except that this variant uses an Encrypted Preferences object, which transparently encrypts the data before storing it, and decrypts it before retrieving it.

// $Id$

package pkg.encrypted;

import java.security.*;
import java.util.prefs.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import ep.*;
import pkg.Util;

public class EncryptedTest
{
  static private final String algorithm = "DES";

  static public void main( String args[] ) throws Exception {
    byte rawKey[] = Util.readFile( "key" );
    DESKeySpec dks = new DESKeySpec( rawKey );
    SecretKeyFactory keyFactory = SecretKeyFactory.getInstance( algorithm );
    SecretKey secretKey = keyFactory.generateSecret( dks );

    Preferences root =
      EncryptedPreferences.userNodeForPackage(
        EncryptedTest.class, secretKey );

    root.put( "transparent", "encryption" );

    Preferences subnode = root.node( "subnode" );
    subnode.put( "also", "encrypted" );

    root.exportSubtree( System.out );
  }
}