1 /*
2  * Copyright 2014 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_HMAC_KEY_H_
18 #define SYSTEM_KEYMASTER_HMAC_KEY_H_
19 
20 #include "symmetric_key.h"
21 
22 namespace keymaster {
23 
24 const size_t kMinHmacLengthBits = 64;
25 const size_t kMinHmacKeyLengthBits = 64;
26 const size_t kMaxHmacKeyLengthBits = 2048;  // Some RFC test cases require >1024-bit keys
27 
28 class HmacKeyFactory : public SymmetricKeyFactory {
29   public:
HmacKeyFactory(const KeymasterContext * context)30     explicit HmacKeyFactory(const KeymasterContext* context) : SymmetricKeyFactory(context) {}
31 
32     keymaster_error_t LoadKey(const KeymasterKeyBlob& key_material,
33                               const AuthorizationSet& additional_params,
34                               const AuthorizationSet& hw_enforced,
35                               const AuthorizationSet& sw_enforced,
36                               UniquePtr<Key>* key) const override;
37 
38     OperationFactory* GetOperationFactory(keymaster_purpose_t purpose) const override;
39 
40   private:
key_size_supported(size_t key_size_bits)41     bool key_size_supported(size_t key_size_bits) const override {
42         return key_size_bits > 0 && key_size_bits % 8 == 00 &&
43                key_size_bits >= kMinHmacKeyLengthBits && key_size_bits <= kMaxHmacKeyLengthBits;
44     }
45     keymaster_error_t validate_algorithm_specific_new_key_params(
46         const AuthorizationSet& key_description) const override;
47 };
48 
49 class HmacKey : public SymmetricKey {
50   public:
HmacKey(const KeymasterKeyBlob & key_material,const AuthorizationSet & hw_enforced,const AuthorizationSet & sw_enforced,keymaster_error_t * error)51     HmacKey(const KeymasterKeyBlob& key_material, const AuthorizationSet& hw_enforced,
52             const AuthorizationSet& sw_enforced, keymaster_error_t* error)
53         : SymmetricKey(key_material, hw_enforced, sw_enforced, error) {}
54 };
55 
56 }  // namespace keymaster
57 
58 #endif  // SYSTEM_KEYMASTER_HMAC_KEY_H_
59