An Efficient Revocation Scheme for Vehicular Ad-Hoc Networks

In Vehicular Ad-Hoc Networks (VANETs), the distribution of certificate revocation information is a security issue to provide safety and efficiency in the transportation system. Most of the current approaches are based on distributing a Certificate Revocation List (CRL) that incurs a large communication overhead, storage space, and checking time. In this work, we propose an efficient revocation scheme based on the use of fog computing and Merkle hash trees replacing the time consuming CRL checking process. More specifically, we divide the roadway into several domains, in which fog nodes manage the vehicles in a localized manner. Then, we utilize Merkle hash trees to provide a highly scalable way to disseminate the revocation information and ensure the integrity of the certificate's status. The performance analysis is carried out to demonstrate the effectiveness of our scheme in terms of verification delay compared with the conventional mechanisms.