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_HKDF_H_
18 #define SYSTEM_KEYMASTER_HKDF_H_
19 
20 #include "kdf.h"
21 
22 #include <keymaster/serializable.h>
23 
24 #include <keymaster/UniquePtr.h>
25 
26 namespace keymaster {
27 
28 /**
29  * Rfc5869Sha256Kdf implements the key derivation function specified in RFC 5869 (using SHA256) and
30  * outputs key material, as needed by ECIES. See https://tools.ietf.org/html/rfc5869 for details.
31  */
32 class Rfc5869Sha256Kdf : public Kdf {
33   public:
~Rfc5869Sha256Kdf()34     ~Rfc5869Sha256Kdf() {}
Init(Buffer & secret,Buffer & salt)35     bool Init(Buffer& secret, Buffer& salt) {
36         return Init(secret.peek_read(), secret.available_read(), salt.peek_read(),
37                     salt.available_read());
38     }
39 
Init(const uint8_t * secret,size_t secret_len,const uint8_t * salt,size_t salt_len)40     bool Init(const uint8_t* secret, size_t secret_len, const uint8_t* salt, size_t salt_len) {
41         return Kdf::Init(KM_DIGEST_SHA_2_256, secret, secret_len, salt, salt_len);
42     }
43 
44     bool GenerateKey(const uint8_t* info, size_t info_len, uint8_t* output,
45                      size_t output_len) override;
46 };
47 
48 }  // namespace keymaster
49 
50 #endif  // SYSTEM_KEYMASTER_HKDF_H_
51