Game Theory-Based Optimal Defense Strategies For Cyber Attack In WSNs

With the rapid development of wireless communication, wireless sensor networks have become a hotspot in the research field of computer networks. Wireless sensor networks have a lot of advantages, and they are widely used. But there are also some problems in wireless sensor networks, such as limited energy, limited storage capacity and limited communication capacity, these inherent create a great security risk, which makes wireless sensor networks vulnerable to be attacked. After suffering Cyber attacks, the networks will receive serious losses, and these losses are generally difficult to restore. To avoid this results, networks need good defense strategies. Nowadays, there is a wide range of defense strategies to resist different types of Cyber attacks, but these defense strategies are determined by the characteristics of Cyber attacks, and the effects of the defense strategies are still limited. So it is important to optimize the defense strategies.Game theory is the study of interaction relationship between attenders. If the attacker who makes Cyber attacks in wireless sensor networks is regarded as one of the attenders in game model, and the defender who determines the defense strategies is the other one, then the interaction between the attacker and the defender could be studied by game theory. So this thesis combines game theory model with wireless sensor networks, and study optimal defense strategies for Cyber attacks. The works of this thesis are the followings:Firstly, this thesis describes the importance of wireless sensor networks, Cyber attacks and defense strategies. After the description, this thesis describes the game theory and presents a viewpoint that optimizing the defense strategies for Cyber attacks based on game theory.Secondly, this thesis analyzes the wireless sensor networks and its topology. After that, this thesis introduces some Cyber attacks, defense strategies, and basic concepts of game theory.Thirdly, this thesis makes two game models to analyze optimal defense strategies, which is a zero-sum game model and a non-zero-sum game model. After study the characteristics of wireless sensor networks, this thesis proposes two optimal defense strategies—— an optimal threshold in firewall and an optimal punishment in intrusion detection system. Then this thesis sets the game model. The attenders in the game model is an attacker who makes Cyber attacks and a defender who resists the Cyber attacks. The actions of the attenders are the configurations which the attacker and the defender can adjust. In the process of game, the attacker can choose his attack strategies, and the defender can choose his optimal defense strategies. After computing, both the attacker and the defender can get their condition when equilibrium state is got, and the defender can get best configurations when his strategies meets the condition. After all of these computation, a complete game model would be constituted.Finally, this thesis verifies the effectiveness of the optimal defense strategies. After simulating environment of the wireless sensor networks, this thesis computes the equilibrium state in the experiment. The defender can get his optimal defense strategies when his configuration meets the condition of the equilibrium. At last, this thesis compares the optimal defense strategies with non-optimal defense strategies, and verifies the effectiveness of the optimal defense strategies.