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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_SYMMETRIC_KEY_H_
     18 #define SYSTEM_KEYMASTER_SYMMETRIC_KEY_H_
     19 
     20 #include <keymaster/key_factory.h>
     21 
     22 #include "key.h"
     23 
     24 namespace keymaster {
     25 
     26 class SymmetricKey;
     27 
     28 class SymmetricKeyFactory : public KeyFactory {
     29   public:
     30     explicit SymmetricKeyFactory(const KeymasterContext* context) : KeyFactory(context) {}
     31 
     32     keymaster_error_t GenerateKey(const AuthorizationSet& key_description,
     33                                   KeymasterKeyBlob* key_blob, AuthorizationSet* hw_enforced,
     34                                   AuthorizationSet* sw_enforced) const override;
     35     keymaster_error_t ImportKey(const AuthorizationSet& key_description,
     36                                 keymaster_key_format_t input_key_material_format,
     37                                 const KeymasterKeyBlob& input_key_material,
     38                                 KeymasterKeyBlob* output_key_blob, AuthorizationSet* hw_enforced,
     39                                 AuthorizationSet* sw_enforced) const override;
     40 
     41     virtual const keymaster_key_format_t* SupportedImportFormats(size_t* format_count) const override;
     42     virtual const keymaster_key_format_t* SupportedExportFormats(size_t* format_count) const override {
     43         return NoFormats(format_count);
     44     };
     45 
     46   private:
     47     virtual bool key_size_supported(size_t key_size_bits) const = 0;
     48     virtual keymaster_error_t
     49     validate_algorithm_specific_new_key_params(const AuthorizationSet& key_description) const = 0;
     50 
     51     const keymaster_key_format_t* NoFormats(size_t* format_count) const {
     52         *format_count = 0;
     53         return NULL;
     54     }
     55 };
     56 
     57 class SymmetricKey : public Key {
     58   public:
     59     ~SymmetricKey();
     60 
     61     virtual keymaster_error_t key_material(UniquePtr<uint8_t[]>* key_material, size_t* size) const;
     62     virtual keymaster_error_t formatted_key_material(keymaster_key_format_t, UniquePtr<uint8_t[]>*,
     63                                                      size_t*) const {
     64         return KM_ERROR_UNSUPPORTED_KEY_FORMAT;
     65     }
     66 
     67     const uint8_t* key_data() const { return key_data_.get(); }
     68     size_t key_data_size() const { return key_data_size_; }
     69 
     70   protected:
     71     SymmetricKey(const KeymasterKeyBlob& key_material, const AuthorizationSet& hw_enforced,
     72                  const AuthorizationSet& sw_enforced, keymaster_error_t* error);
     73 
     74   private:
     75     size_t key_data_size_;
     76     UniquePtr<uint8_t[]> key_data_;
     77 };
     78 
     79 }  // namespace keymaster
     80 
     81 #endif  // SYSTEM_KEYMASTER_AES_KEY_H_
     82