A Study Of Message Authentication And Privacy Preservation In Vehicular Ad Hoc Networks

As the infrastructure of future intelligent transportation system, Vehicular ad hocnetworks (VANET) enables communication between vehicles, which can not onlyimprove traffic efficiency and increase the drivers’ experience and comfort, but alsodecrease or avoid the traffic accidents as soon as possible, so VANET can play arevolutionary role in traffic regulation. However due to vulnerability and openness ofthe wireless network, it is very easy for VANET to be attack, for example, bogusinformation attack, message replay attack, sybil attack, denial of service (DOS) attackand so on. To countermeasure and mitigate the potential threats, a well-developedsecurity protocol for VANET should meet the following requirements: data originauthentication and integrity, revocability, anonymity, non-reputation and so on.Meanwhile, VANET should preserve the users’ privacy, so the protocol is a conditionalauthentication scheme. Also, VANET consists of a huge number of vehicles, whichrequires one efficient security protocol.VANET is one special kind of mobile ad hoc networks, its node’ number is large andevery node moves very fast, so the net topology changes quickly, furthermore, thewireless channel is not stable, but the nodes moves along the road and the vehicles’engine can provide enough power for communication units. These characteristics bringa lot of challenges in the aspects of security and privacy. So one special kind of securityprotocol should be designed for VANET message authentication.According to the actual state of VANET, some preliminary research and explorationis developed on message authentication and privacy preservation, some new securityprotocols are proposed as follows:(1) Vehicle-based classification authentication protocol is proposed for the messagein VANET, vehicles are classified into categories according to privacy preservation,some vehicles need privacy, for example the private cars, so the messages from them areverified by group signature, the others needn’t privacy preservation, for example theRSUs and the public vehicles, so the messages from them should be verified byidentity-based signature.(2) Information security framework is proposed for VANET, all nodes and entitiesare managed by hierarchies and levels, group-based regulation mode is exploited, thevehicles can roam to send and receive messages, every domain has one CA whichresponsible for signing private keys for the vehicles in the local and regulating the localRSUs, every domain has one TA (Tracing Authority) responsible for revoking the illegal vehicles and punishing them.(3)An efficient privacy-preserving authentication scheme is proposed,in whichgroup signature and ID-based signcryption are exploited, the vehicles can apply andrenew their private key from the CA by signcryption, and then they can signing andsending messages on behalf of the group, which can preserve the users’ privacy.(4)Batch verification algorithms are proposed, these algorithms can verify a largenumber of messages in the approximately fixed period of time, and the verification timecan not increase along with the increase of messages, which can reduce response timeon the safety messages and resist the DOS attack.(5)Quantitative comparison and determination is employed to handle the conflictinginformation, which can increase the difficulty of invasion in minimum cost.(6)A distributed key management protocol for VANET, in which vehicles can obtainone pseudonym by certificateless signcryption, then the vehicles can use the pseudonymto hide themselves, so they can securely sign and send messages, the receivers canverify a large number of the messages by batch verification, the protocol can meet therequirements of the large-scale VANET.