Design And Implementation Of Hierarchical Blockchains For Internet Of Vehicles

With the development of the automotive industry and the popularization of 5G networks,the Internet of Vehicles(IoV)has ushered in rapid development.However,the data privacy and data trustworthy problems in the IoV have also been exposed.Once a vehicle is connected to the network,the user’s private data can be easily traced through the data sent by the vehicle,such as name,location,whereabouts,etc.Once the user’s data is leaked,it will threaten the personal privacy and safety of the owner.However.once user privacy is protected or anonymity is used,users may post false messages without revealing their identities.Blockchain technology has developed rapidly in recent years and has been applied in many fields.In order to solve the data privacy problem in the IoV,this thesis introduces blockchain technology into the IoV by taking advantages of the decentralization and anonymity of blockchain.In order to solve the data trustworthy problem in the IoV,this thesis designs several new mechanisms in the blockchain-based IoV system.However,due to the characteristics of the large number and fast mobility of IoV nodes,the application of blockchain technology to IoV faces problems such as poor scalability of the blockchain and the lack of incentives for users to share information,which makes the system difficult for continuous running.On account of these considerations,the thesis first introduces the motivation and research status of introducing blockchain technology into the IoV.Based on the analysis of the current data privacy and data trustworthy problems in the IoV,the thesis summarizes the state of the art of blockchain technology,analyzes the benefits and existing problems of using blockchain to solve the data privacy and data trustworthy problems of IoV,and summarizes the current existing solutions and problems that use blockchain technology to solve the data security and data trustworthy problems of IoV.Secondly,considering the characteristics of numerous vehicular nodes and their strong mobility and the limitations of blockchain technology,the thesis proposes a hierarchical blockchains architecture for IoV.The stability of the system is enhanced by designing network nodes with different functions and responsibilities.At the same time,the programmable features of smart contracts are fully used and some key mechanisms for IoV services are designed.In order to protect the user’s data privacy in the process of vehicle data transmission and reception,an encryption mechanism for data is designed.In order to achieve the interoperability of data in the hierarchical blockchains,a data synchronization mechanism is designed.In order to encourage more vehicles to contribute data to networks,an incentive mechanism is designed,which rewards vehicles for uploading data and charges part of the fee when requiring data from the networks.In order to solve the trust of the data on the chain,this thesis designs a scoring mechanism for vehicles.Furthermore,the data transmission and reception process of the route planning service in the IoV is also designed,which can explain how to use the key mechanisms designed in this thesis to solve the problems of data privacy and data trustworthy,and explain how the hierarchical blockchains and the corresponding mechanisms can be used to introduce IoV services.Finally,an Ethereum network implementing the designed hierarchical blockchains and the corresponding mechanisms is built,and the route planning service is realized.The on-chain delay under different block difficulty coefficients has been tested.In addition,the ns3 simulation tool has also been used to test the total delay of the route planning service and the delays generated by the various processes of the service,in order to analyze the overhead of the blockchain for the IoV services.