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_KEM_H_
18#define SYSTEM_KEYMASTER_KEM_H_
19
20#include <keymaster/serializable.h>
21
22#include "openssl_utils.h"
23
24namespace keymaster {
25
26// Kem is an abstract class that provides an interface to a key encapsulation
27// mechansim primitive. A key encapsulation mechanism works just like a
28// public-key encryption scheme, except that the encryption algorithm takes no
29// input other than the recipient’s public key. Instead, the encryption algorithm
30// generates a pair (K, C0), where K is a bit string of some specified length,
31// and C0 is an encryption of K, that is, the decryption algorithm applied to C0
32// yields K.
33class Kem {
34  public:
35    virtual ~Kem(){};
36
37    // For a key encapsulation mechanism, the goal of encryption is to take the recipient's public
38    // key, and to generate a pair (K, C0), where K is a bit string of some specified length,
39    // and C0 is an encryption of K.
40    virtual bool Encrypt(const Buffer& peer_public_value, Buffer* output_clear_key,
41                         Buffer* output_encrypted_key) = 0;
42    virtual bool Encrypt(const uint8_t* peer_public_value, size_t peer_public_value_len,
43                         Buffer* output_clear_key, Buffer* output_encrypted_key) = 0;
44
45    // Decrypt takes an encrypted key, and outputs its clear text.
46    // Decrypt takes ownership of \p private_key.
47    virtual bool Decrypt(EC_KEY* private_key, const Buffer& encrypted_key, Buffer* output_key) = 0;
48    virtual bool Decrypt(EC_KEY* private_key, const uint8_t* encrypted_key,
49                         size_t encrypted_key_len, Buffer* output_key) = 0;
50};
51
52}  // namespace keymaster
53
54#endif  // SYSTEM_KEYMASTER_KEM_H_
55