content: /*
   * Copyright (C) 2010 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.google.android.vending.licensing;
  
  /**
   * Interface used as part of a {@link Policy} to allow application authors to obfuscate
   * licensing data that will be stored into a SharedPreferences file.
   * <p>
   * Any transformation scheme must be reversable. Implementing classes may optionally implement an
   * integrity check to further prevent modification to preference data. Implementing classes
   * should use device-specific information as a key in the obfuscation algorithm to prevent
   * obfuscated preferences from being shared among devices.
   */
  public interface Obfuscator {
  
      /**
       * Obfuscate a string that is being stored into shared preferences.
       *
       * @param original The data that is to be obfuscated.
       * @param key The key for the data that is to be obfuscated.
       * @return A transformed version of the original data.
       */
      String obfuscate(String original, String key);
  
      /**
       * Undo the transformation applied to data by the obfuscate() method.
       *
       * @param original The data that is to be obfuscated.
       * @param key The key for the data that is to be obfuscated.
       * @return A transformed version of the original data.
       * @throws ValidationException Optionally thrown if a data integrity check fails.
       */
      String unobfuscate(String obfuscated, String key) throws ValidationException;
  }
  