Research On Message Authentication In Vehicular Ad Hoc Networks

In recent years, due to the rapid increase of vehicles in the city, it brings people seriousproblems, such as traffic accidents, traffic congestion, energy consumption and so on. Aimingto reduce such problems, Vehicle Ad Hoc Networks (VANETs) has become a hot topic forresearch scholars all over the world. The topic in the theoretical research contents mainlyinclude protecting the users’ privacy, authentication problems of messages transmitted amongvehicles, as well as a variety of network services (such as electronic toll collection,entertainment download, Internet access etc.).Because VANETs is an open network, so it suffers from various attacks, such as the manin the middle attack, forging signatures, tampering with the message. In order to avoid theseattacks, it is necessary to authenticate messages transmitted in the network. But as a result ofVANETs’ dynamics, instability of the network’s topological structure, short life link of themessage, causing such message authentication has distinction with the traditional messageauthentication. For example, a vehicle in VANETs may receive thousands of messages fromnearby vehicles in a short period of time. In order to make a right decision for driving, thedriver should make a rapid authentication of such numbers messages, rather than the singlemessage authentication. The rapid authentication called batch authentication is the study ofthis article. On the other hand, using cryptographic tools such as signature and encryption toconstruct some authentication protocols suitable for VANETs is also an important content ofthis study.This thesis deeply researches the vehicle ad hoc network protocols, especially in theprocess of the message authentication protocols, obtains the following achievements:1. Analysis on the protocol of Zhang et al, we found the signature length is too long oftheir protocol during the signing phase, resulting an excessive computation and time in thenext batch verification. By making an appropriate changing of Boneh et al. group signaturescheme, we propose an improved message authentication protocol for vehicularcommunications. However, we soon discovered this protocol is not perfect, because when thebatch verification fail, that is all signatures verified contain some invalid signatures, we didnot give out a corresponding solution. Then based on the idea of law et al.[47], we propose asuitable for our protocol error signature algorithm, which makes our protocol is morecomplete. Our analysis shows that under the same level of security, our protocol is moreefficient than the protocol of Zhang et al.2. Based on background of vehicle ad hoc networks application, that is users in thenetworks need access to some services from service providers. Combining heavy communication capacity, high speed mobility of the network, we refine the networks andadopt signature and encryption techniques, we propose a secure and robust session keyestablishment protocol. To our knowledge, similar protocols about this background are rare.In addition, most protocols of the vehicular ad hoc networks used a large amount of highconsumption of bilinear mappings or exponent operations, but we use many low consumptionof hash operations and XOR operations in our protocol. So we have reasons to believe thatour proposed protocol has a high efficiency. In addition, by our analysis, our protocol alsosatisfies many security requirements.