1 // 2 // Copyright (C) 2020 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 #pragma once 17 18 #include <keymaster/random_source.h> 19 20 struct ESYS_CONTEXT; 21 22 namespace cuttlefish { 23 24 /** 25 * Secure random number generator, pulling data from a TPM. 26 * 27 * RandomSource is used by the OpenSSL HMAC key and AES key implementations. 28 */ 29 class TpmRandomSource : public keymaster::RandomSource { 30 public: 31 TpmRandomSource(ESYS_CONTEXT* esys); 32 virtual ~TpmRandomSource() = default; 33 34 keymaster_error_t GenerateRandom( 35 uint8_t* buffer, size_t length) const override; 36 37 keymaster_error_t AddRngEntropy(const uint8_t*, size_t) const; 38 private: 39 ESYS_CONTEXT* esys_; 40 }; 41 42 } // namespace cuttlefish 43