1/*
2 * Copyright (C) 2018 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 */
16package android.hardware.authsecret@1.0;
17
18/**
19 * This security HAL allows vendor components to be cryptographically tied to
20 * the primary user's credential. For example, security hardware could require
21 * proof that the credential is known before applying updates.
22 *
23 * This HAL is optional so does not require an implementation on device.
24 */
25interface IAuthSecret {
26    /**
27     * When the primary user is unlocked, this method is passed a secret to
28     * prove that is has been successfully unlocked. The primary user can either
29     * be unlocked by a person entering their credential or by another party
30     * using an escrow token e.g. a device administrator.
31     *
32     * The first time this is called, the secret must be used to provision state
33     * that depends on the primary user's secret. The same secret must be passed
34     * on each call until the next factory reset.
35     *
36     * Upon factory reset, any dependence on the secret must be removed as that
37     * secret is now lost and must never be derived again. A new secret must be
38     * created for the new primary user which must be used to newly provision
39     * state the first time this method is called after factory reset.
40     *
41     * The secret must be at least 16 bytes.
42     *
43     * @param secret blob derived from the primary user's credential.
44     */
45    oneway primaryUserCredential(vec<uint8_t> secret);
46};
47