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A robust distributed authorization scheme for availability enhancement in VANET

Vehicular Ad Hoc Networks (VANETs) have become one of the platforms for relaying information in the Internet of Things (IOT). Unfortunately, VANETs can be vulnerable to several forms of attacks and threats. To overcome such problems, security and availability enhancing mechanisms are essential for VANET deployment. Clustering is one of the key points in VANETs, where cluster structure can facilitate overcoming some of the challenging issues in VANETs specially the security requirements. Secured and stable clustering play a significant role in VANET credibility. In terms of security, we shouldn't rely on centralized Certificate Authority (CA) in each cluster as it could be vulnerable to potential attacks and hence participant nodes in this cluster might lose access to it. Therefore, deploying decentralized approach for distributing the authorization inside clusters will overcome the authorization problem if the CA disappears or went missing. In this paper, we propose a distributed authorization scheme in which the role of the CA is distributed among a number of trusted nodes forming Certification Authority Committee (CAC). Since the certification authority, nodes' information and network secrets will be distributed over the CAC members, the presented scheme effectively guarantees both cluster stability and availability of security services. We analyzed the proposed scheme in terms of computation and storage complexity, communications overhead as well as network service availability. The results show that the availability of network services is greatly enhanced in adverse network status. This enhancement will be at the cost of negligible increment in storage complexity and communications overhead whereas the computational complexity is relative to the other distributed schemes.