Research On Privacy Security And Authentication Protocol In VANETs

In recent years,with the continuous development of the economy and the emergence of new technologies,vehicles have increasingly become an indispensable travel tool in people's lives.However,how to intelligently and efficiently control and manage an increasing number of vehicles and improve traffic efficiency becomes a hard problem.As an important development trend,Vehicle ad hoc networks(VANETs)are used for communication between vehicles to provide information such as weather conditions,road conditions,traffic congestion and their own status,which is of great significance for improving traffic safety and efficiency.In this scenario,in order to ensure secure communication in VANETs,it is a crucial task to authenticate the entity that sends the message and distribute the group key among the authenticated vehicles.At the same time,in VANETs,hundreds of signed messages need to be authenticated by the roadside unit(RSU)in a short period of time.At the same time,in VANETs,considering the network bandwidth limitation and computational overhead,hundreds of signed messages need to be authenticated by the roadside unit(RSU)in a short period of time,so how to design an efficient aggregation signature scheme has become a question worth discussing.Based on the above problems in VANETs,combined with the current research status,this thesis mainly addresses the main problems in VANETs that exist in identity authentication,group key agreement and message aggregation signature.The main work and contributions of this thesis are as follows:(1)We propose a conditional privacy protection authentication scheme based on hash function.Based on the characteristics of the hash function,the vehicle is not authenticated by using complex bilinear pairing and elliptic curve cryptography to prevent the interference of illegal vehicles and ensure the legitimacy of the source.At the same time,a group key agreement mechanism based on the Chinese Remainder Theorem(CRT)is proposed to distribute the group key for the certified vehicle and to update the group key according to the vehicle when joining the group and leaving the group.That is,we have designed an admission rule that only legally certified vehicles can enter VANETs,and only legitimate vehicles can communicate with other legal group members via group keys.For the authentication process,we demonstrate the reliability and security of the proposed scheme through security analysis under the random oracle model.In addition,through detailed experimental demonstration,in the process of anonymous message generation and verification,the results analysis shows that compared with the existing schemes,our scheme not only meets the security privacy requirements,but also has significant advantages in overall computing overhead and communication overhead.(2)For signed messages sent by different vehicles in VANETs,how to aggregate signatures to meet the authentication process with faster efficiency is also a problem worth studying.In this thesis,we propose a certificateless aggregation signature scheme based on elliptic curve cryptography for communication between vehicles and infrastructure.Aggregation signature allows individual signature on different messages from different vehicles to be aggregated into one short signature.At the same time,no additional certificates need to be carried in each authentication process,reducing communication overhead.We show that the proposed certificateless aggregate signature scheme implements conditional privacy protection and meets privacy requirements.In addition,in the random oracle model,the security of the scheme is proved by the difficulty of adaptive selection message attack and computation of discrete logarithm problem(ECDLP)on elliptic curve.Finally,through experimental demonstration,compared with the existing schemes,the results analysis shows that our scheme has obvious advantages in the aggregation signature verification and batch verification,which makes it have better applicability.