Matthew S. Bradbury

Fake source-based source location privacy in wireless sensor networks

The development of novel wireless sensor network (WSN) applications, such as asset monitoring, has led to novel reliability requirements. One such property is source location privacy (SLP). The original SLP problem is to protect the location of a source node in a WSN from a single distributed eavesdropper attacker. Several techniques have been proposed to address the SLP problem, and most of them use some form of traffic analysis and engineering to provide enhanced SLP. The use of fake sources is considered to be promising for providing SLP, and several works have investigated the effectiveness of the fake sources approach under various attacker models. However, very little work has been done to understand the theoretical underpinnings of the fake source technique. In this paper, we (i) provide a novel formalisation of the fake sources selection problem; (ii) prove the fake sources selection problem to be NP‐complete; (iii) provide parametric heuristics for three different network configurations; and (iv) show that these heuristics provide (near) optimal levels of SLP under appropriate parameterisation. Our results show that fake sources can provide a high level of SLP. Our work is the first to investigate the theoretical underpinnings of the fake source technique. Copyright

Towards Understanding Source Location Privacy in Wireless Sensor Networks through Fake Sources

Source location privacy is becoming an increasingly important property in wireless sensor network applications, such as asset monitoring. The original source location problem is to protect the location of a source in a wireless sensor network from a single distributed eavesdropper attack. Several techniques have been proposed to address the source location problem, where most of these apply some form of traffic analysis and engineering to provide enhanced privacy. One such technique, namely fake sources, has proved to be promising for providing source location privacy. Recent research has concentrated on investigating the efficiency of fake source approaches under various attacker models. In this paper, we (i) provide a novel formalisation of the source location privacy problem, (ii) prove the source location privacy problem to be NP-complete, and (iii) provide a heuristic that yields an optimal level of privacy under appropriate parameterisation. Crucially, the results presented show that fake sources can provide a high, sometimes optimal, level of privacy.

Efficient fault-tolerant collision-free data aggregation scheduling for wireless sensor networks

This paper investigates the design of fault-tolerant TDMA-based data aggregation scheduling (DAS) protocols for wireless sensor networks (WSNs). DAS is a fundamental pattern of communication in wireless sensor networks where sensor nodes aggregate and relay data to a sink node. However, any such DAS protocol needs to be cognisant of the fact that crash failures can occur. We make the following contributions: (i) we identify a necessary condition to solve the DAS problem, (ii) we introduce a strong and weak version of the DAS problem, (iii) we show several impossibility results due to the crash failures, (iv) we develop a modular local algorithm that solves stabilising weak DAS and (v) we show, through simulations and an actual deployment on a small testbed, how specific instantiations of parameters can lead to the algorithm achieving very efficient stabilisation. We formalise the problem of data aggregation scheduling and prove some impossibility results.We develop an efficient modular algorithm that solves stabilising data aggregation scheduling in the presence of crash failures.We show, through simulation and an actual deployment, the viability of our approach.

Evaluating the Impact of Broadcast Rates and Collisions on Fake Source Protocols for Source Location Privacy

Providing source location privacy has become a relevant issue for protocols used in the context of wireless sensor networks. In particular, where an asset is monitored using a wireless sensor network it is often the case that the location of the asset being monitored should be concealed from those eavesdropping on the network. The use of fake sources represents an approach to addressing the source location privacy problem. This paper explores practical factors for the configuration and application of fake source protocols, with a focus on the interplay between the broadcast rates of sensor nodes, message collisions and achieved privacy. Combined with existing work in energy efficient fake source protocols, these contributions evidence the existence of an effective range of broadcast rates for fake source protocols.

Phantom walkabouts in wireless sensor networks

As wireless sensor networks (WSNs) have been applied across a spectrum of application domains, the problem of source location privacy (SLP) has emerged as a significant issue, particularly in security-critical situations. In the seminal work on SLP, phantom routing was proposed as a viable approach to address SLP. However, recent work has shown some limitations of phantom routing such as poor performance with multiple sources. In this paper, we propose phantom walkabouts, a novel version and more general version of phantom routing, which performs phantom routes of variable lengths. Through extensive simulations we show that phantom walkabouts provides high SLP levels with a low message overhead and hence, low energy usage.

A decision theoretic framework for selecting source location privacy aware routing protocols in wireless sensor networks

Abstract Source location privacy (SLP) is becoming an important property for a large class of security-critical wireless sensor network applications such as monitoring and tracking. Many routing protocols have been proposed that provide SLP, all of which provide a trade-off between SLP and energy. Experiments have been conducted to gauge the performance of the proposed protocols under different network parameters such as noise levels. As that there exists a plethora of protocols which contain a set of possibly conflicting performance attributes, it is difficult to select the SLP protocol that will provide the best trade-offs across them for a given application with specific requirements. In this paper, we propose a methodology where SLP protocols are first profiled to capture their performance under various protocol configurations. Then, we present a novel decision theoretic procedure for selecting the most appropriate SLP routing algorithm for the application and network under investigation. We show the viability of our approach through different case studies.

Deconstructing source location privacy-aware routing protocols

Source location privacy (SLP) is becoming an important property for a large class of security-critical wireless sensor network applications such as monitoring and tracking. Much of the previous work on SLP have focused on the development of various protocols to enhance the level of SLP imparted to the network, under various attacker models and other conditions. Others works have focused on analysing the level of SLP being imparted by a specific protocol. In this paper, we focus on deconstructing routing-based SLP protocols to enable a better understanding of their structure. We argue that the SLP-aware routing protocols can be classified into two main categories, namely (i) spatial and (ii) temporal. Based on this, we show that there are three important components, namely (i) decoy selection, (ii) use and routing of control messages and (iii) use and routing of decoy messages. The decoy selection technique imparts the spatial or temporal property of SLP-aware routing. We show the viability of the framework through the construction of well-known SLP-aware routing protocols using the identified components.

Assessing the Performance of Phantom Routing on Source Location Privacy in Wireless Sensor Networks

As wireless sensor networks (WSNs) have been applied across a spectrum of application domains, the problem of source location privacy (SLP) has emerged as a significant issue, particularly in safety-critical situations. In seminal work on SLP, phantom routing was proposed as an approach to addressing the issue. However, results presented in support of phantom routing have not included considerations for practical network configurations, omitting simulations and analyses with larger network sizes. This paper addresses this shortcoming by conducting an in-depth investigation of phantom routing under various network configurations. The results presented demonstrate that previous work in phantom routing does not generalise well to different network configurations. Specifically, under certain configurations, it is shown that the afforded SLP is reduced by a factor of up to 75.

Towards optimal source location privacy-aware TDMA schedules in wireless sensor networks

Abstract Source Location Privacy (SLP) is becoming important for wireless sensor networks where the source of messages is kept hidden from an attacker. In this paper, we conjecture that similar traffic perturbation to altering the routing protocol can be achieved at the link layer through assignment of time slots to nodes. This paper presents a multi-objective optimisation problem where SLP, schedule latency and final attacker distance are criteria. We employ genetic algorithms to generate Pareto-optimal schedules using two fitness criteria, examining the Pareto efficiency of selecting either and confirming the efficiency by performing simulations which show a near optimal capture ratio.

A Near-Optimal Source Location Privacy Scheme for Wireless Sensor Networks

As interest in using Wireless Sensor Networks (WSNs) for deployments in scenarios such as asset monitoring increases, the need to consider security and privacy issues also becomes greater. One such issue is that of Source Location Privacy (SLP) where the location of a source in the network needs to be kept secret from a malicious attacker. Many techniques have been proposed to provide SLP against an eavesdropping attacker. Most techniques work by first developing an algorithm followed by extensive performance validation. Differently, in this paper, we model the SLP problem as an Integer Linear Programming optimization problem. Using the IBM ILOG CPLEX optimiser, we obtain an optimal solution to provide SLP. However, that solution is centralised (i.e., requires network-wide knowledge) making the solution unsuitable for WSNs. Therefore, we develop a distributed version of the solution and evaluate the level of privacy provided by it. The solution is hybrid in nature, in that it uses both spatial and temporal redundancy to provide SLP. Results from extensive simulations using the TOSSIM WSN simulator indicate a 1% capture ratio is achievable as a trade-off for an increase in the delivery latency.