In this article we present a survey of secure ad hoc routing protocols for mobile wireless networks. A mobile ad hoc network is a collection of nodes that is connected through a wireless medium forming rapidly changing topologies. The widely accepted existing routing protocols designed to accommodate the needs of such self-organized networks do not address possible threats aiming at the disruption of the protocol itself. The assumption of a trusted environment is not one that can be realistically expected; hence, several efforts have been made toward the design of a secure and robust routing protocol for ad hoc networks. We briefly present the most popular protocols that follow the table-driven and the source-initiated on-demand approaches. Based on this discussion we then formulate the threat model for ad hoc routing and present several specific attacks that can target the operation of a protocol. In order to analyze the proposed secure ad hoc routing protocols in a structured way we have classified them into five categories: solutions based on asymmetric cryptography; solutions based on symmetric cryptography; hybrid solutions; reputation-based solutions; and a category of add-on mechanisms that satisfy specific security requirements. A comparison between these solutions can provide the basis for future research in this rapidly evolving area.SECURE ROUTING FOR MOBILE AD HOC NETWORKS THIRD QUARTER 2005, VOLUME 7, NO. 3 www.comsoc.org/pubs/surveys uring the last few years we have all witnessed steadily increasing growth in the deployment of wireless and mobile communication networks. Mobile ad hoc networks consist of nodes that are able to communicate through the use of wireless mediums and form dynamic topologies. The basic characteristic of these networks is the complete lack of any kind of infrastructure, and therefore the absence of dedicated nodes that provide network management operations as do the traditional routers in fixed networks. In order to maintain connectivity in a mobile ad hoc network all participating nodes have to perform routing of network traffic. The cooperation of nodes cannot be enforced by a centralized administration authority since one does not exist. Therefore, a network-layer protocol designed for such self-organized networks must enforce connectivity and security requirements in order to guarantee the undisrupted operation of the higherlayer protocols.Unfortunately all of the widely used ad hoc routing protocols have no security considerations and trust all the participants to correctly forward routing and data traffic. This assumption can prove to be disastrous for an ad hoc network that relies on intermediate nodes for packet forwarding. Simulations have shown that if 10 percent to 40 percent of the nodes that participate in an ad hoc network perform malicious operations, then the average throughput degradation reaches 16 percent to 32 percent [1]. Earlier surveys and review papers presenting comparisons of ad hoc routing protocols completely ignored security problems ...

Abstract

A mobile ad hoc network is a collection of nodes that is

We present a policy-driven trading framework for market-based spectrum assignment. Our work allows spectrum consumers to get exclusive access rights through payment of a fee, for a given period of time, and for a given frequency band and location. The key motivation behind our proposal stems from the increased complexity of new spectrum management strategies and the need for extracting the maximum benefit from the available spectrum. In this paper we demonstrate that a policy-driven solution is applicable for the management of spectrum markets, and we present a decentralised and lightweight framework for implementing such markets in networked environments.

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