| Intelligent transportation has become extremely popular and the Internet of vehicles is one of the key technologies supporting intelligent transportation.Using the dedicated short range communication(DSRC),Internet of vehicles allow vehicles to communicate with other vehicles and infrastructure.Besides,vehicles should periodically broadcast beacon messages containing their own status information in accordance with DSRC.The openness of wireless channels and the plaintext broadcasting of beacon messages have brought safety and privacy threats to the Internet of vehicles.This thesis studies the vehicle privacy leakage caused by beacon message broadcasting in the Internet of vehicles and focuses on the location privacy protection of Internet of vehicles based on pseudonym exchange.Attacks on the location privacy of the Internet of vehicles include pseudonym matching attacks and pseudonym linking attacks.The pseudonym linking attacks are divided into syntactic attacks and semantic attacks.This thesis uses actual data sets and analyzes the impact of the three types of attacks on location privacy performance.Results show that when pseudonym changes occur,the location tracking performance of semantic attacks is better than that of pseudonym matching attacks and syntactic attacks.Therefore,this thesis considers semantic attacks as the main location privacy attack method.Considering that existing location privacy protection schemes cannot effectively resist pseudonym linking attacks,this thesis proposes a pseudonym exchange based location privacy protection method.The vehicle decides when to exchange pseudonym based on pre-defined overtaking conditions and broadcasts beacon messages with false status during the pseudonym exchange.Results verify that the proposed method can protect the location privacy of the vehicle and offer the vehicle more autonomy.Using pseudonym exchange to protect location privacy brings a heavy burden to the certification authority and leads to the problem of single failure and poor scalability of the system,which makes the pseudonym management challenging.As for this problem,this thesis proposes a blockchain-based pseudonym management method,which uses blockchain to manage roadside units to prevent data tampering and assigns pseudonym management tasks to roadside units to reduce the burden of certification authorities and the delay of pseudonym exchange reporting;To reduce computational overhead,a proof-of-work consensus mechanism with dynamic hash threshold is also proposed.Results verify that the proposed pseudonym management scheme can reduce the delay of pseudonym exchange reporting and improve throughput.The pseudonym exchange based location privacy protection method and blockchainbased pseudonym management method proposed in the thesis can protect the location privacy of vehicles,reduce the dependence on the certification authority and realize the rapid reporting of pseudonym exchange,which show promising prospects in the future applications. |
