Research On Lightweight Certificate Authority And Privacy Preserving Scheme Based On Consortium Blockchain In Internet Of Vehicles

Internet of Vehicles（Io V）aims to provide location-based services for vehicles.By intelligently collecting and processing various vehicle communication data,Io V can reduce the growing number of road accidents and traffic congestion,and provide nearby vehicles with valuable living information and traffic information.With the rapid development of Io V,an unprecedented amount of data related to vehicles is being generated.Due to the large scale communication and the fast velocity of vehicles,Io V is confronted with latency,packet loss and privacy issues.In place of a could server,a set of appropriately distributed roadside units（RSU）,could interact with vehicles in the vicinity and facilitate instant vehicular communications.However,both distributed vehicles and roadside units are vulnerable to cyber-attacks,or even worse,they may be corrupted by adversaries.Due to the inherent decentralization,anonymity and data consistency features of blockchain,it can be used to improve the security and quality of service of the distributed network.Compared to the public blockchain,consortium blockchain is considered as a type of manage-efficient blockchain architecture that is constantly used for business or government applications.Building Io V on the basis of consortium blockchain can somehow solve the RSU Corruption and enhance privacy.However,it is noted that all data in the blockchain is stored on the public chain,which is vulnerable to background analysis attacks.In other words,the owner of the anonymous account can be identified by means of data analysis etc.It could be said that the anonymity provided by blockchain is weak,strong privacy protection cannot be achieved.In addition,the authorization of nodes in a consortium blockchain requires the introduction of an additional certificate authority,which needs to be based on additional trust and is not in conformity with the decentralized feature of the blockchain.By the way,the authentication process requires frequent interactions with the certificate authority（CA）,resulting in additional communication overhead,and the single-point certificate authority is based on the assumption that the certificate authority is fully trustable.The Contribution of this article is as follows: 1.To address the above issues,a new cryptographic primitive,lightweight threshold certificate authority（LTCA）is proposed in this paper.Specifically,when new users access the network,partial proxy keys are issued by the distributed RSU which serves the role of CA.Users can recover the complete proxy key with no less than a threshold number of partial proxy keys.Using the proxy key,users can issue the certification itself without interaction with an online CA.Compared to traditional CA,in the efficiency aspect,the lightweight feature of LTCA is reflected in the fact that it does not need the participation of an online CA.In the security aspect,LTCA is resistant to single point failure and does not base on the assumption that the certificate authority is totally trustable.2.Based on LTCA,a privacy-preserving vehicular communication protocol is devised.Besides the anonymity provided by blockchain,PPVC update users’ addresses periodically to resist background analysis attacks.In addition,PPVC is conditional privacy preservation,which means that it preserves anonymity and accountability.3.The theoretical and experimental result proves that the proposed LTCA and PPVC reach higher efficiency and security level compared to existing works.