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Unformatted text preview: Reputation Methods for Routing Security for Mobile Ad Hoc Networks* Po-Wah Yau and Chris J. Mitchell Mobile VCE Research Group Information Security Group Royal Holloway, University of London Egham Surrey TW20 OEX, UK [email protected], [email protected] ABSTRACT Mabiie ad hoc networks have inherently very different prop- erties to conventional networks. These new characteristics present major security vulnerabilities; in particular, one side effect of the unique way in which routing protocols operate in ad hoc networks is that many new threats arise. Self- ish nodes are those which do not perform certain opera- tions that the protocol specifies that they should, through a wish to conserve power. Malicious nodes may deliberately disrupt the network using a variety of attacks. This paper discusses reputation mechanisms which have been suggested a5 a means to mitigate the detrimental effect of selAsh and malicious nodes. This paper reveals reasons why complex reputation systems may be too inefficient to use in a mo- bile ad hoc network, where resources are limited. However, suggestions are also made to show how a simple reputation system might be used to enhance the robustness of ad hoc networks. Keywords Routing protocols, network security, mobile network. 1. WTRODUCTION Mobile ad hoc networks have inherently very different properties to conventional networks. An ad hoc network is a collection of nodes forming a temporary or permanent net- work without any support from centralised services. Within a wireless network, a node's transmission range will typi- cally not cover the whole network, so end-to-end commu- nication may require routing information via several nodes. This is why ad hoc networks are sometimes referred to as networks, where resources can be limited. Section 2 introduces the security issues in ad hoc net- works. Section 3 give an overview of reputation systems and how they have been applied to ad hoc networks. Section 4 discusses the use of reputation systems, analysing how repu- tations are calculated and how they are distributed. Section 5 suggests how simple reputation systems can be used to help improve the security of ad hoc networks. Finally, sec- tion 6 concludes the paper. The following terms are used in this document, but may be used differently elsewhere. A node is a device which has a network interface participating in routing in a mobile ad hoc network. It may or may not be mobile, and may also be part of another network. It is important to realise that a node can actually be.a large network, or it could just be a single mobile device such as a mobile phone. An originator node is a node which originates a data packet, intended for a certain destination node. A node is a neighbow node of another node if it is only one hop away and within direct transmission range. If the destination node is not a neighbour node of the originator node, the data packet will have to traverse a multi-hop route consisting of intennediate nodes. In a a multi-hop route consisting of intennediate nodes....
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- Spring '11
- Computer network, routing protocol, D istributed Reputation System