content: /*
   * Copyright (C) 2015 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 android.security.keystore;
  
  import android.security.KeyStore;
  import android.security.KeyStoreException;
  
  /**
   * Helper for streaming a crypto operation's input and output via {@link KeyStore} service's
   * {@code update} and {@code finish} operations.
   *
   * <p>The helper abstracts away to issues that need to be solved in most code that uses KeyStore's
   * update and finish operations. Firstly, KeyStore's update operation can consume only a limited
   * amount of data in one go because the operations are marshalled via Binder. Secondly, the update
   * operation may consume less data than provided, in which case the caller has to buffer the
   * remainder for next time. The helper exposes {@link #update(byte[], int, int) update} and
   * {@link #doFinal(byte[], int, int, byte[], byte[]) doFinal} operations which can be used to
   * conveniently implement various JCA crypto primitives.
   *
   * @hide
   */
  interface KeyStoreCryptoOperationStreamer {
      byte[] update(byte[] input, int inputOffset, int inputLength) throws KeyStoreException;
      byte[] doFinal(byte[] input, int inputOffset, int inputLength, byte[] signature,
              byte[] additionalEntropy) throws KeyStoreException;
      long getConsumedInputSizeBytes();
      long getProducedOutputSizeBytes();
  }
  