Document Type

Other

Publication Date

5-2004

Abstract

In recent years, several researchers have studied the vulnerabilities present in the encryption protocols and authentication mechanisms associated with 802.11-based networks. This research has led to the creation of protocol extensions and replacement proposals such as WPA, 802.11i, and 802.1X. In addition, Denial of Service attacks that can be launched against 802.11-based networks, with relative ease and impunity, have been studied. Simultaneously, researchers studying the limitations of wireless networks have turned their attention to one of the inherent limitation of wireless devices, namely, power consumption. Research in this area has been focused in understanding the impact of the network interface card, and its effect on the overall power consumption. The main research result has been the design and implementation of adaptive power management algorithms that complement the power saving modes of 802.11 devices. Unfortunately, study of wireless networks protocols from the perspective of their security profile, that is, how do the power consumption limitations of wireless devices affect security, is less well understood.

In this manuscript, we will first review the current limitations of security protocols associated with 802.11 networks. We will develop a general model that will help us understand how the current set of security related protocols affect the energy consumption of the devices. This model is general enough to cover the security energy tradeoffs at different layers of wireless network protocols in use. In the model, we use a decision-theoretic framework. This framework requires both an energy cost function called CE and a security-reliability measure, RM. The energy cost function, CE, is the cost, both in energy and other systems resources, of applying a countermeasure MK against a specific protocol vulnerability Vi. The security-reliability measure, RM, represents the level or measure of the security-reliability attained by countermeasure MK on the overall security of the system. Having refined such a framework, we present our initial analysis of popular security protocol, such as WEP, TKIP. Preliminary results showed that significant improvements can be obtained by constraining the time frame where security needs to be guaranteed.

Based on these results, a new wireless encryption protocol, called E-SEC, or Energy efficient secure protocol is introduced. This protocol has the potential to minimize power consumption while maximizing the security profile of the network as a whole.

DOI

WPI-CS-TR-04-12

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