Cluster Head and RREQ based Detection and Prevention of Gray hole and Denial of Service Attack in WSN

Wireless sensor network is a type of network which have no communications pattern for communication between nodes, any node can easily join the network and leave the network so attacks are more probable. Gray hole is one of such attacks and it is tough to detect since malicious node switches behavior between normal node and malicious node. For detection and prevention of gray hole attacks our proposed technique is based on Cluster head and RREQ based approach in WSN. In our proposed technique we select a node which has the highest energy as a cluster head and remaining node are marked as work as cluster member. For each node we decide a threshold for sending RREQ if any node generate RREQ more than threshold then we check its RREP threshold value if it�s less than one than cluster head will conclude this node as a malicious node and broadcast its node id so that all other nodes also mark it as malicious node and drop the request arrive from this malicious node and for gray hole detection.