1 /*
2  * Copyright (C) 2022 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 
17 package android.security.keystore2;
18 
19 import android.annotation.NonNull;
20 import android.security.KeyStoreSecurityLevel;
21 import android.system.keystore2.Authorization;
22 import android.system.keystore2.KeyDescriptor;
23 
24 import java.security.PrivateKey;
25 import java.security.interfaces.XECPrivateKey;
26 import java.security.spec.NamedParameterSpec;
27 import java.util.Optional;
28 
29 /**
30  * X25519 Private Key backed by Keystore.
31  * instance of {@link PrivateKey} and {@link XECPrivateKey}
32  *
33  * @hide
34  */
35 public class AndroidKeyStoreXDHPrivateKey extends AndroidKeyStorePrivateKey
36         implements XECPrivateKey {
AndroidKeyStoreXDHPrivateKey( @onNull KeyDescriptor descriptor, long keyId, @NonNull Authorization[] authorizations, @NonNull String algorithm, @NonNull KeyStoreSecurityLevel securityLevel)37     public AndroidKeyStoreXDHPrivateKey(
38             @NonNull KeyDescriptor descriptor, long keyId,
39             @NonNull Authorization[] authorizations,
40             @NonNull String algorithm,
41             @NonNull KeyStoreSecurityLevel securityLevel) {
42         super(descriptor, keyId, authorizations, algorithm, securityLevel);
43     }
44 
45     @Override
getParams()46     public NamedParameterSpec getParams() {
47         return NamedParameterSpec.X25519;
48     }
49 
50     @Override
getScalar()51     public Optional<byte[]> getScalar() {
52         /* An empty Optional if the scalar cannot be extracted (e.g. if the provider is a hardware
53          * token and the private key is not allowed to leave the crypto boundary).
54          */
55         return Optional.empty();
56     }
57 }
58