Privacy-preserving Protocols For VANET Based On Digital Signatures

With the rapid development of the vehicular Ad hoc network technology,human travel efficiency has been improved greatly.However,caused by vehicle fast and high frequency moving,network topology changes constantly,in addition,because of the inherent openness property of wireless network transmission medium,so they not only put network security at huge risk,but also increased the design and implementation of the vehicular Ad hoc network security solution.Therefore,safety issues are big challenges which the vehicular Ad hoc network must face.After analyzing and summarizing current security research of vehicular Ad hoc network,although there have been a lot of research in the field of security,but the existing security schemes still cannot meet the diversity applications and the privacy requirements of vehicular Ad hoc network,how to solve vehicular Ad hoc network privacy protection problem efficiently is becoming more and more urgent.This paper is dedicated to construct the privacy protection scheme of vehicular Ad hoc communication network.The proposed solution is traceable,namely when the communication content is controversial,the solution can track the source of the message.Because proxy signature and ring signature,ring signcryption technology plays an important role in privacy protection area,in this paper,we use these algorithms as underlying cryptographic algorithms for designing privacy protected vehicular Ad hoc network communication algorithm.We analyzed and researched these cryptography algorithm,and make further efforts for designing new privacy protection solution suitable for vehicular Ad hoc network in order to ensure the related safety requirements of the network.Contributions and innovations of this paper is mainly manifested in the following three parts:1.Analyzed proxy re-signature based vehicular Ad hoc network privacy protection algorithm safety property and put forward the improvement solution.In Proxy signature scheme,vehicle sent the signature of the message to the roadside unit,after roadside unit verified message,it execute proxy re-signature on behalf of the Certification Center.X-H programs use third-party proxy re-signatures to secure the privacy of sources.In this paper,we performed security analysis for X-H,found that they can't resist enemy's conspiracy attack,therefore we presents the corresponding improvement algorithm,the improved algorithm overcomes the collusion attack and meet the safety demand of privacy protection of Ad hoc network as well.2.The proposed vehicle network privacy protection scheme based on conditionally anonymous ring signcryption.Proposed a vehicular Ad hoc network privacy protection scheme based on conditional anonymity ring signcryption.Conditional anonymity ring signcryption scheme can satisfy the confidentiality of the message,the anonymity of signers and achieve non-repudiation of signers.This paper combine the P-LJ multi-receivers' anonymous ring signcryption idea and conditional anonymity property of Z-SK idea together,put forward a conditional anonymous ring signature scheme and applies this scheme in vehicular Ad hoc network,forming a vehicular Ad hoc network privacy protection scheme based on conditional anonymous ring signcryption.Since this scheme don't need a third party to assist in tracking phase,so efficiency and safety of tracking is higher,and the feasibility of application in practical environment is increased at the same time.3.Simulated vehicular Ad hoc network privacy protection scheme based on conditional anonymous ring signcryption by using the NS3 tool.Analyzed the statistics of time delay,throughput,and packet loss rate of different vehicle under different scheme,finally showed the result in the form of a chart.The results show that the proposed vehicular Ad hoc network privacy protection scheme based on conditional anonymous ring signcryption is better than other solutions in terms of efficiency,and has more use value in real life.