Middle-East Journal of Scientific Research 23 (9): 2198-2204, 2015 ISSN 1990-9233 © IDOSI Publications, 2015 DOI: 10.5829/idosi.mejsr.2015.23.09.22451 Corresponding Author: Mohammed Ali Hussain, Department of Electronics and Computer Engineering, KL University, Guntur Dist andhra Pradesh, India. E-mail: dralihussain@kluniversity.in. 2198 An Optimal Voting Mechanism for Cluster-Based Certificate Revocation in Mobile Ad Hoc Networks Mohammed Ali Hussain and Satuluri Naganjaneyulu 1 2 Department of Electronics and Computer Engineering, KL University, Guntur Dist, A.P., India 1 Department of Information Technology, 2 Lakireddy Bali Reddy College of Engineering, Krishna Dist, A.P., India Abstract: Mobile Adhoc Networks (MANETS) consists of nodes having routing capabilities. MANETs does not have any fixed infrastructure. Due to this reason, MANET nodes are vulnerable to various types of attacks includes worm hole attack, spoofing attack, black hole attack, DOS, non repudiation attack. There are many existing methods for identifying and blocking such attacker nodes. But the attacker node can perform its operations even though it is blocked. So the main task is to completely disconnect that node from the entire network. This can be done with the help of digital certificates. Nodes having valid digital certificates are considered as legal nodes. Otherwise they are considered as attacker nodes. So a node with a legal digital certificate can communicate with other nodes in the network. Digital certificates are issued by Certificate authority (CA). Certificate authority digitally signs each certificate with its private key and then issue to the nodes. Now nodes can verify each others certificate before communication. If a node is identified as vulnerable then the certificate is revoked from it and then disconnected from the network. In our research work, we use voting mechanism to identify attacker nodes and then revoke certificates from them. In many cases malicious node may make fake claims, this result in revoking certificates from legal nodes. Then the question arises in front of CA that the claim is trustable or not. Therefore the certificate revocation method must be able to distinguish fake claims from valid ones. Key words: Certificate Authority Certificate revocation Cluster MANET Voting INTRODUCTION The nodes in a fixed network use cables for communication. They have a central administrator for controlling and monitoring the communication. A mobile ad hoc network does not have any fixed infrastructure or any administrator. They are self configuring networks. Fig. 1 shows an example of mobile ad hoc network. MANET allows any node can communicate with any other node wirelessly by forming a network. So nodes can join and leave a network freely. Thus the number of nodes at an instance can increase or decrease in a MANET. The main problem here is security. For example an attacker node can enter into a MANET freely and can launch attacks. Thus security [1] becomes a major concern in Fig. 1: An Example Mobile Ad Hoc Network MANET. Various types of attacks include black hole attack, worm hole attack, denial of service attack, non Attacks on MANET can come in any direction and repudiation attack. any node in the network can become a target for the