The Research Of Security And Privacy Preservation Mechanisms For VANET

Vehecular ad hoc networks(VANET)is one of the core technologies of intelligent transportation system,which can improve the security of vechiele,the transport efficiency and driving experience.However,VANET faces on multiple specific attacks except the traditional wireless network security threats beacause of the characteristics of itself and wireless channel.Once compromised,VANET will lead to very serious consequences,which may be the loss of property,even people's lives.Thus,it is very meaningful to research the security and privacy preservation mechanisms.In current schemes,the message authentication protocol is usually used to ensure the validity of message.Similarly,to preserve the privacy of users,pseudonym mechanism is proposed.The proposed trust models are used to evaluate the reliability of message and node.This dissertation focuses on the researches in related three fields,and proposes several feasible alternatives,which are as follow:(1)To improve the authentation efficiency and manage the identity of node,we proposed a hybrid authentication protocol,in which the certificate authority(CA)is in charge of issuing a certificate for every registered node.The unique certificate can be used to manage and revoke the identity of node and authenticate the validity of node.The roadside unit(RSU)issues the master key for the vehicle in the communicate range.Once obtaining it,vehicle can generate the anonymous identity to sign the beacon message by identity-based signature technology.In vehicle-to-vehicle(V2V)communication,the receiver only needs to verify the signature in the message authentication phase.When vehicle is accused as a malicious node,CA can easily revoke its certificate to stop participating in the network again.Thus,our proposed scheme can meet the requirement of authentication efficiency of VANET,as well as revoking the identity of node conveniently.(2)The registered vehicle holds a lot of pseudonyms to change for privacy preservation in pseudonym mechanism,which brings the storage overhead and the waste of pseudonym.When a vehicle is revoked,CA also needs to revoke all of it pseudonyms.The size of certificate revocation list will be immeasurable.Beside,the efficiency of pseudonym change is low in some privacy preserving schemes.To meet the aforementioned problems,we propose a trigger-based pseudonym exchange scheme,in which every vehicle only needs to hold one anonymous certificate.Vehicles exchange their pseudonyms by related algorithms according to the designed trigger.Compared with the pseudonym change scheme,a pseudonym associates the different vehicle at different period in the pseudonym exchange scheme,which meets the aforementioned overhead issue and improves the efficiency and privacy level.(3)To reconcile the conflict of privacy preservation and reputation evaluation,we propose a distributed trust scheme for pseudonym-enabled privacy preservation in VANETs.In this scheme,the centrul the centralized reputation server records and manages all of the reputations of vehicles,which are used to evaluate the long-term reliability.RSU is in charge of evaluating the reliability of vehicle in its communication range,and then assigns the reputation label certificate for them.The centralized reputation server updates the reputation value according to the feedback of RSU.Other vehicle evaluates the reliability of a vehicle by the reputation label certificate,which represents the long-term turst and short-term behavior of a vehicle.To avoid being tracked as the additional clue,the reputation label certificate is ambiguous in manifestation phase.