content: /*
   * Copyright (C) 2017 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.android.server.locksettings.recoverablekeystore;
  
  import android.security.keystore.AndroidKeyStoreSecretKey;
  
  /**
   * Private key stored in AndroidKeyStore. Used to wrap recoverable keys before writing them to disk.
   *
   * <p>Identified by a generation ID, which increments whenever a new platform key is generated. A
   * new key must be generated whenever the user disables their lock screen, as the decryption key is
   * tied to lock-screen authentication.
   *
   * <p>One current platform key exists per profile on the device. (As each must be tied to a
   * different user's lock screen.)
   *
   * @hide
   */
  public class PlatformEncryptionKey {
  
      private final int mGenerationId;
      private final AndroidKeyStoreSecretKey mKey;
  
      /**
       * A new instance.
       *
       * @param generationId The generation ID of the key.
       * @param key The secret key handle. Can be used to encrypt WITHOUT requiring screen unlock.
       */
      public PlatformEncryptionKey(int generationId, AndroidKeyStoreSecretKey key) {
          mGenerationId = generationId;
          mKey = key;
      }
  
      /**
       * Returns the generation ID of the key.
       */
      public int getGenerationId() {
          return mGenerationId;
      }
  
      /**
       * Returns the actual key, which can only be used to encrypt.
       */
      public AndroidKeyStoreSecretKey getKey() {
          return mKey;
      }
  }
  