Towards modeling wireless location privacy

Abstract

The lack of a formal model in wireless location privacy protection research makes it difficult to evaluate new location privacy protection proposals, and difficult to utilize existing research results in anonymous communication into this new problem. In this paper, we analyze a wireless location privacy protection system (WLP2S), and generalize it to a MIX based formal model, which includes a MIX, a set of MIX's user, and a intruder of MIX. In addition, we also use information theory approach to define anonymity and measures of this model, and describe the characteristics of observation process in WLP2S in detail. Two benefits arise from our model. Firstly, it provides a means of evaluating the privacy level of proposed location privacy protection protocols. We use the measures of proposed formal model to study the performance of our novel silent period technique. Simulation results reveal the role of many parameters-such as users' mobility pattern and intruders' tracking accuracy- on users' privacy level. The results shed more light on improving our defense protocol. Secondly, our approach provides a link between existing defense and attack protocols in MIX research and the new location privacy protection problem. By utilizing the formal model, we conducted preliminary studies in identifying potential attacks, and improve the performance of existing defense protocol. This study results an extension of existing defense protocols. Those simulation and analytical results demonstrates the promising potential of our model. © Springer-Vorlag Berlin Heidelberg 2006.