/*
 * 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 KeyStore service's update and finish operations. 
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 update and doFinal operations which can be used to conveniently implement various JCA crypto primitives. 
@hide
/**
 * 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();
}