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Abstract:
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Due to severe resource limitations and often lack of centralized infrastructure , providing security in wireless sensor networks is a great challenge . Misbehavior due to malicious or faulty nodes can significantly degrade the performance of such networks . Therefore , countermeasures against denial of service (DoS ) attacks and node misbehavior are essential requirements . We argue that the conventional view of security based on cryptography techniques is not sufficient for securing wireless sensor networks . In this dissertation , we investigate a novel framework by proposing three approaches for security enforcement in such networks that range from prevention of DoS attacks to secure routing . Prevention of DoS attacks focuses on the formal assessment of the properties of cooperation enforcement mechanisms used to detect and prevent malicious behavior of sensor nodes .
Our first proposed approach is called Utility based Dynamic Source Routing (UDSR ) . It is based on non -cooperative game theory , where players of the game are sensor nodes . Players can occasionally misbehave . In this game , we demonstrate that in order to reach equilibrium , where no rational player has any incentive to deviate and to maximize the profit for the network (i .e . , the least amount of false detections ) , a sensor network shall isolate those nodes that act maliciously . These nodes have the minimum amount of utility in the game . This approach provides an automatic method for the social mechanisms of reputation and cooperation .
Our second proposed approach is called Secure Auction based Routing (SAR ) . The assumption is that rational players always plan to maximize their profit over time . Here the key to solve this problem is when a node uses other nodes in the network to forward its own packets , it has to contribute to the network life ( by forwarding other nodes packets ) in order to be entitled to use them in the future . To enable such networks to keep functioning despite the presence of misbehaving nodes , we propose a mechanism such that nodes prefer to gain reputation in the network . Nodes willing to do so must compete against each other , where the competition is based on auction theory . A node's truthful bidding remains a dominant strategy and to have a secure routing protocol , malicious nodes who do not bid truthfully shall be isolated .
Our third proposed approach deals with detection of malicious nodes , based on repeated games . The benefit of this approach is the impact of a large group of players in the sense that the strategy chosen by a player does not only depend on one malicious node's perception of the game , but also on the group policy for all players . The strategy of a sensor node is to decide whether to cooperate with other nodes . This approach identifies non participating nodes and isolates them . We show that infinite repetition can be the key for obtaining equilibrium behavior , which could not be reached if the game were played once or for a known finite number of times . Implementation results on a sensor network testbed indicate that the repeated game based approach , conditioned on past histories of players , detects the malicious nodes more accurately . |