1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.security.keystore;
18
19import android.security.KeyStore;
20import android.security.KeyStoreException;
21
22/**
23 * Helper for streaming a crypto operation's input and output via {@link KeyStore} service's
24 * {@code update} and {@code finish} operations.
25 *
26 * <p>The helper abstracts away to issues that need to be solved in most code that uses KeyStore's
27 * update and finish operations. Firstly, KeyStore's update operation can consume only a limited
28 * amount of data in one go because the operations are marshalled via Binder. Secondly, the update
29 * operation may consume less data than provided, in which case the caller has to buffer the
30 * remainder for next time. The helper exposes {@link #update(byte[], int, int) update} and
31 * {@link #doFinal(byte[], int, int, byte[], byte[]) doFinal} operations which can be used to
32 * conveniently implement various JCA crypto primitives.
33 *
34 * @hide
35 */
36interface KeyStoreCryptoOperationStreamer {
37    byte[] update(byte[] input, int inputOffset, int inputLength) throws KeyStoreException;
38    byte[] doFinal(byte[] input, int inputOffset, int inputLength, byte[] signature,
39            byte[] additionalEntropy) throws KeyStoreException;
40    long getConsumedInputSizeBytes();
41    long getProducedOutputSizeBytes();
42}
43