||In recent years, more and more people have invested a lot of effort in Vehicular Ad Hoc Networks (VANETs) to study and discuss. VANETs is a mobile communication technology that combines the wireless devices equipped on the vehicles and around the roadside. Based on the technology, we can consider moving vehicles as nodes. Nodes will link between each other. Finally, it will constitute a mobile network.|
In this environment, vehicles can transmit traffic information via wireless channels and increase driving efficiency and the traffic safety based on those receiving information. Because the information is transmitted through wireless method, it may be subjected to a variety of attacks (i.e. tampering, forging… etc.). In order to prevent the message from attacks, we are in need of Roadside Unit (RSU) to do message authentication to guarantee the validity of sources and message integrity during transmitting message processes. Furthermore, we can utilize the anonymous identity to protect the secret of vehicle safety.
In this paper, we propose a mechanism based on Chameleon Hashing and HMAC to do identity verification and message authentication. In our proposed method, TA and RSU retain their own secret values and utilize them to generate their chameleon hash values. After RSU and vehicles register to TA, TA will issue them new secret values. In addition, we can calculate pairing values (intra value or inter value) between vehicle and vehicle or vehicle and RSU based on whether they have the same issuer. After proposing anonymous request to RSU, vehicle can not only utilize chameleon hash value, HMAC, and Diffie-Hellman key exchange to do identity verification and message authentication, but also combine pairing value and HMAC to do secure communication. When vehicles are suffered from attacks, TA and RSU can look up the recorded tables, which record public identity and anonymous identity, to revoke malicious attacker’s identity in the revocation list.
In summary, the scheme we proposed can satisfy the desired characteristics for VANETs, namely authentication, non-repudiation, confidentiality, conditional anonymity and un-traceability. The comparisons with the related works show that the proposed scheme is superior to the related ones in functionality and performance.