Vehicular Networks (VNs) seek to provide, among other applications, safer driving conditions. To do so, vehicles need to periodically broadcast safety messages providing preciseposition information ...

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Mix-Zones for Location Privacy in Vehicular Networks

Covering attack detection, malware response, algorithm and mechanism design, privacy, and risk management, this comprehensive work applies unique quantitative models derived from decision, control, and game theories to understanding diverse network security problems It provides the reader with a system-level theoretical understanding of network security, and is essential reading for researchers interested in a quantitative approach to key incentive and resource allocation issues in the field It also provides practitioners with an analytical foundation that is useful for formalising decision-making processes in network security

Network Security: A Decision and Game-Theoretic Approach

As a prime target of the quality of privacy in vehicular ad hoc networks (VANETs), location privacy is imperative for VANETs to fully flourish. Although frequent pseudonym changing provides a promising solution for location privacy in VANETs, if the pseudonyms are changed in an improper time or location, such a solution may become invalid. To cope with the issue, in this paper, we present an effective pseudonym changing at social spots (PCS) strategy to achieve the provable location privacy. In particular, we first introduce the social spots where several vehicles may gather, e.g., a road intersection when the traffic light turns red or a free parking lot near a shopping mall. By taking the anonymity set size as the location privacy metric, we then develop two anonymity set analytic models to quantitatively investigate the location privacy that is achieved by the PCS strategy. In addition, we use game-theoretic techniques to prove the feasibility of the PCS strategy in practice. Extensive performance evaluations are conducted to demonstrate that better location privacy can be achieved when a vehicle changes its pseudonyms at some highly social spots and that the proposed PCS strategy can assist vehicles to intelligently change their pseudonyms at the right moment and place.

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Pseudonym Changing at Social Spots: An Effective Strategy for Location Privacy in VANETs

We present a path perturbation algorithm which can maximize users location privacy given a quality of service constraint. This work concentrates on a class of applications that continuously collect location samples from a large group of users, where just removing user identifiers from all samples is insufficient because an adversary could use trajectory information to track paths and follow users footsteps home. The key idea underlying the perturbation algorithm is to cross paths in areas where at least two users meet. This increases the chances that an adversary would confuse the paths of different users. We first formulate this privacy problem as a constrained optimization problem and then develop heuristics for an efficient privacy algorithm. Using simulations with randomized movement models we verify that the algorithm improves privacy while minimizing the perturbation of location samples.

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Protecting Location Privacy Through Path Confusion

So far, the problem of positioning in wireless networks has been studied mainly in a nonadversarial setting. In this paper, we analyze the resistance of positioning techniques to position and distance spoofing attacks. We propose a mechanism for secure positioning of wireless devices, that we call verifiable multilateration. We then show how this mechanism can be used to secure positioning in sensor networks. We analyze our system through simulations.

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Secure positioning in wireless networks

The advance of ISM-band radio-based tracking systems (for example, wireless LAN-based tracking system) extends the application of location-based services (LBS), but it also threatens to allow the movement of users to be tracked when they are transmitting frames. Several protection methods based on periodic address updates have already been proposed. However, new correlation attacks, which utilize the correlation between the old and new addresses of the same node, can defeat current protection methods. To combat such attacks, we propose the concept of a silent period. A silent period is defined as a transition period between the use of new and old pseudonyms, when a node is not allowed to disclose either the old or the new address. Through analysis, we find that a silent period should contain a constant period and a variable period. The effect of the constant period is to mix the spatial relation between the node's disappearing points and emerging points. The variable period mixes the temporal relation between the node's disappearing times and emerging times. We evaluate the performance of the silent period through simulation. The results show that the silent period proposal significantly reduces the duration of time a node can be tracked continuously. There are still many open research problems before random address can be implemented to protect wireless location privacy, but silent period protocol is the first step to realizing it.

Enhancing wireless location privacy using silent period

In a wireless communication network, it is possible to locate a user and track its trajectory based on its transmission, during communication with access points. This type of tracking leads to the breach of a user's location privacy. Prior solutions to this problem enhances user's location privacy at the expense of communication Quality of Service(QoS) degradation. In this paper, we propose silent cascade to enhance a user' location privacy by trading users' delay in silent cascade for anonymity. As a result, it avoids the problem of QoS degradation in prior solutions. Furthermore, we abstract silent cascade as a mix-network based formal model, and use this model to evaluate the performance of silent cascade. Study results prove the effectiveness of silent cascade under different types of QoS requirements. Besides, we also derive the optimal configuration of silent cascade to achieves target anonymity within minimum duration of time. and the theoretical upper bound of a silent cascade's anonymity.

Silent cascade: enhancing location privacy without communication QoS degradation

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.

Towards modeling wireless location privacy

A method for combating the tracking of a mobile transceiver, the mobile transceiver forming a node in a wireless communication network which has at least one other node, the method comprising the steps for enabling, until a first time, the transmission of a radio packet that depends upon a first anonymous address; calculating, dependent on a privacy level for the mobile transceiver, a second time; enabling, from the second time, the transmission of a radio packet that depends upon a second anonymous address; and disabling, between the first time and the second time, the transmission of a radio packet that depends upon either the first anonymous address or the second anonymous address.

Hiroshi Yamane

Papers

Enhancing wireless location privacy using silent period

Silent cascade: enhancing location privacy without communication QoS degradation

Towards modeling wireless location privacy

Wireless location privacy

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