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      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_AES_KEY_H_
     18 #define SYSTEM_KEYMASTER_AES_KEY_H_
     19 
     20 #include <openssl/aes.h>
     21 
     22 #include "symmetric_key.h"
     23 
     24 namespace keymaster {
     25 
     26 const size_t kMinGcmTagLength = 12 * 8;
     27 const size_t kMaxGcmTagLength = 16 * 8;
     28 
     29 class AesKeyFactory : public SymmetricKeyFactory {
     30   public:
     31     AesKeyFactory(const KeymasterContext* context) : SymmetricKeyFactory(context) {}
     32 
     33     keymaster_algorithm_t registry_key() const { return KM_ALGORITHM_AES; }
     34 
     35     keymaster_error_t LoadKey(const KeymasterKeyBlob& key_material,
     36                               const AuthorizationSet& hw_enforced,
     37                               const AuthorizationSet& sw_enforced,
     38                               UniquePtr<Key>* key) const override;
     39 
     40     OperationFactory* GetOperationFactory(keymaster_purpose_t purpose) const override;
     41 
     42   private:
     43     bool key_size_supported(size_t key_size_bits) const override {
     44         return key_size_bits == 128 || key_size_bits == 192 || key_size_bits == 256;
     45     }
     46     keymaster_error_t validate_algorithm_specific_new_key_params(
     47         const AuthorizationSet& key_description) const override;
     48 };
     49 
     50 class AesKey : public SymmetricKey {
     51   public:
     52     AesKey(const KeymasterKeyBlob& key_material, const AuthorizationSet& hw_enforced,
     53            const AuthorizationSet& sw_enforced, keymaster_error_t* error)
     54         : SymmetricKey(key_material, hw_enforced, sw_enforced, error) {}
     55 };
     56 
     57 }  // namespace keymaster
     58 
     59 #endif  // SYSTEM_KEYMASTER_AES_KEY_H_
     60