Defending Reputation System against False Recommendation in Mobile Ad Hoc Network

Reputation system can make a mobile ad hoc network be more cooperative and securer. However it can be cheated by the propagation of rumor produced by malicious or selfish node for using second-hand observation. As the malicious and selfish nodes are more and more trickish, false recommendation emerged dynamically and randomly. Hence, most traditional solution can hardly mitigate the threat from liars. In this paper, we proposed a novel schema which is based on game theory to detect false recommendation. In our approach, we define recommendation game (RG) and construct the strategy of reputation requester, "tit for tat", against dynamical and random action of malicious and selfish node. At last, we verify the RG in the COSR (cooperative on-demand secure route) through GloMoSim. Results show that RG could reduce the number of false recommendation, mitigate the threat of lies and make reputation system of COSR be robust and stable even if a lot of liars exist in the MANET.