Improvement of Local Greedy Algorithm in GEAR

Wireless sensor networks (WSNs) is believed to be the first of the top ten technologies that will change the world in the future. With the development of WSNs in the military and commercial fields, the security of WSNs is becoming more and more important. The classical security mechanisms, namely authentication and encryption, can prevent some outsider attacks; however, these mechanisms are inefficient in detecting selective forwarding attacks on compromised nodes. Based on the observations above, in this paper, an improved greedy algorithm based on reputation evaluation mechanism is proposed to enforce cooperation among the nodes of WSNs and defend against the selective forwarding attacks. The performance of the improved greedy algorithm is verified by simulation, and the simulation result shows that the proposed algorithm can effectively resist the attacks of internal malicious nodes, it has better performance than the original greedy algorithm in terms of packet delivery ratio and drop ratio while there exist attack nodes.