| Summary: | 碩士 === 國立清華大學 === 資訊系統與應用研究所 === 95 === Wireless network technology is demanding and continually growing. Mobile ad hoc networks (MANETs) are extensively used in military and civilian applications. Their dynamic and flexibility allow the networks to be easily set up without the requirement of a predetermined infrastructure.
However, unconstrained dynamic nature of the topology of mobile ad hoc networks makes them vulnerable to various types of attacks including routing attacks. Black hole attacks belong to one such type of attacks which disrupt the routing functions in MANETs. Rushing attacks also enable the attackers with limited resources and no cryptographic material to destroy the operation in MANETs. Wormhole attacks which are more sophisticated attacks still can easily crumble the connection in MANETs.
The packet-dropping problem usually accompanies these routing attacks.
The attackers claim that they have routes to forward data packets.
However, when the data packets are routed through them, they drop these data packets that are supposed to be forwarded. These attacks greatly reduce the performance of the networks. Moreover, they are able to partition the network and degrade the connectivity of the network.
So, we propose a robust scheme to defense these routing attacks in MANETs and improve the performance of the networks. In our scheme, we design a strong detection system to effectively detect malicious nodes in the networks. It can work properly even if multiple malicious nodes are collusive and try to circumvent the detection. For effectively utilization of the observation in the networks, we design a secure and cooperative reputation system. The proposed reputation system can prevent false accusation created by malicious nodes. Finally, we propose two mechanisms to defense various types of routing attacks. Our experiments show that the proposed mechanisms can successfully improve the throughput of the network.
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