Type of Document Dissertation Author Hu, Jiangyi Author's Email Address firstname.lastname@example.org URN etd-04092007-181236 Title Trust Management in Mobile Wireless Networks: Security and Survivability Degree Doctor of Philosophy Department Computer Science, Department of Advisory Committee
Advisor Name Title Alec Yasinsac Committee Member Breno de Medeiros Committee Member Lois W. Hawkes Committee Member Mio Washington Committee Member Zhenhai Duan Committee Member Keywords
- Wireless Network
- Mobile Network
- Network Security
Date of Defense 2007-03-29 Availability unrestricted AbstractIn this dissertation we study the security and survivability of wireless mobile network
systems in two distinct threat models: the Byzantine threat model and the selfish node
Wireless mobile networks are collections of self-organizing mobile nodes with dynamic
topologies and have no fixed infrastructure. Because of their dynamic ad hoc nature, these
networks are particularly vulnerable to security threats. The security of such systems is,
to a large extent, based on trust associations. There are several ways in which trust can
be supported in a network system. The way we adopt is to establish a secure public key
management infrastructure (PKI). This enables basic cryptographic functionalities, such as
integrity, privacy, etc. However, due to the dynamic character of a wireless mobile network
and its ad hoc topology changes, the trust associations cannot depend on any pre-established
trust relations and must support a flexible, uncertain and incomplete trust model.
One of our main goals in this dissertation is to analyze the distributed nature of trust in
wireless mobile networks and to consider approaches that manage trust based only on locally
available information. In our analysis for this problem we use the traditional Byzantine
attack model. After reviewing the trust models proposed in the literature we propose an
extension that supports a distributed trust management infrastructure. In this model the
trust is distributed horizontally via multiple disjoint trust flows. Compared to the traditional
hierarchical trust distribution, our approach is appropriate for dynamic wireless systems for
which there are no central trust authorities.
A second goal is to manage trust based on the good behavior of nodes. Mobile wireless
networks rely heavily on node collaboration. However, since the nodes are often batterypowered, they may behave selfishly to preserve power. The threat model for this application
is restricted to selfish node attacks.
We present a simple and e±cient reputation system, Locally Aware Reputation System
(LARS) that mitigates selfish node behavior. We explore methods that stimulate node
cooperation in mobile wireless networks, and analyze the reputation systems proposed in the
literature. The performance of LARS is evaluated in terms of its packet delivery ratio, its
end-to-end delay and its overhead, and compared to the other reputation systems proposed in the literature.
Finally, to enhance the security and survivability of wireless mobile networks against selfish threats, we propose a mechanism that will trace selfish node behavior.
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