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_KDF_H_
18#define SYSTEM_KEYMASTER_KDF_H_
19
20#include <hardware/keymaster_defs.h>
21#include <keymaster/android_keymaster_utils.h>
22#include <keymaster/serializable.h>
23
24#include <keymaster/UniquePtr.h>
25
26namespace keymaster {
27
28/**
29 * A base class for wrapping different key derivation functions.
30 */
31class Kdf {
32  public:
33    virtual ~Kdf() { memset_s(secret_key_.get(), 0, secret_key_len_); };
34    Kdf();
35    bool Init(keymaster_digest_t digest_type, const uint8_t* secret, size_t secret_len,
36              const uint8_t* salt, size_t salt_len);
37    virtual bool GenerateKey(const uint8_t* info, size_t info_len, uint8_t* output,
38                             size_t output_len) = 0;
39
40  protected:
41    bool Uint32ToBigEndianByteArray(uint32_t number, uint8_t* output);
42    UniquePtr<uint8_t[]> secret_key_;
43    size_t secret_key_len_;
44    UniquePtr<uint8_t[]> salt_;
45    size_t salt_len_;
46    bool is_initialized_;
47    keymaster_digest_t digest_type_;
48    size_t digest_size_;
49};
50
51}  // namespace keymaster
52
53#endif  // SYSTEM_KEYMASTER_KDF_H_
54