1 /*
2  * Copyright 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 
17 #ifndef SYSTEM_KEYMASTER_KEY_EXCHANGE_H_
18 #define SYSTEM_KEYMASTER_KEY_EXCHANGE_H_
19 
20 #include <openssl/ec.h>
21 
22 #include <keymaster/serializable.h>
23 
24 namespace keymaster {
25 
26 /**
27  * KeyExchange is an abstract class that provides an interface to a
28  * key-exchange primitive.
29  */
30 class KeyExchange {
31   public:
~KeyExchange()32     virtual ~KeyExchange() {}
33 
34     /**
35      * CalculateSharedKey computes the shared key between the local private key
36      * (which is implicitly known by a KeyExchange object) and a public value
37      * from the peer.
38      */
39     virtual bool CalculateSharedKey(const Buffer& peer_public_value, Buffer* shared_key) const = 0;
40     virtual bool CalculateSharedKey(const uint8_t* peer_public_value, size_t peer_public_value_len,
41                                     Buffer* shared_key) const = 0;
42 
43     /**
44      * public_value writes to |public_value| the local public key which can be
45      * sent to a peer in order to complete a key exchange.
46      */
47     virtual bool public_value(Buffer* public_value) const = 0;
48 };
49 
50 }  // namespace keymaster
51 
52 #endif  // SYSTEM_KEYMASTER_KEY_EXCHANGE_H_
53