References of "Woerndl, Wolfgang"
     in
Bookmark and Share    
Full Text
See detailContext-based Pseudonym Changing Scheme for Vehicular Adhoc Networks
Emara, Karim Ahmed Awad El-Sayed UL; Woerndl, Wolfgang; Schlichter, Johann

E-print/Working paper (2016)

Vehicular adhoc networks allow vehicles to share their information for safety and traffic efficiency. However, sharing information may threaten the driver privacy because it includes spatiotemporal ... [more ▼]

Vehicular adhoc networks allow vehicles to share their information for safety and traffic efficiency. However, sharing information may threaten the driver privacy because it includes spatiotemporal information and is broadcast publicly and periodically. In this paper, we propose a context-adaptive pseudonym changing scheme which lets a vehicle decide autonomously when to change its pseudonym and how long it should remain silent to ensure unlinkability. This scheme adapts dynamically based on the density of the surrounding traffic and the user privacy preferences. We employ a multi-target tracking algorithm to measure privacy in terms of traceability in realistic vehicle traces. We use Monte Carlo analysis to estimate the quality of service (QoS) of a forward collision warning application when vehicles apply this scheme. According to the experimental results, the proposed scheme provides a better compromise between traceability and QoS than a random silent period scheme. [less ▲]

Detailed reference viewed: 98 (1 UL)
Full Text
Peer Reviewed
See detailOn Evaluation of Location Privacy Preserving Schemes for VANET Safety Applications
Emara, Karim Ahmed Awad El-Sayed UL; Woerndl, Wolfgang; Schlichter, Johann

in Computer Communications (2015), 63(1), 11--23

Location privacy in vehicular ad hoc networks has gained considerable attention in the past few years. The majority of studies concern changing pseudonyms to prevent linking messages of the same pseudonym ... [more ▼]

Location privacy in vehicular ad hoc networks has gained considerable attention in the past few years. The majority of studies concern changing pseudonyms to prevent linking messages of the same pseudonym. However, the precise spatiotemporal information included in beacons (i.e., timestamp, position, speed and heading) makes them vulnerable to tracking even if they are completely anonymous. One of the most important issues in designing location privacy scheme is to preserve the quality of service of the application. This issue is more significant for safety applications, since they require precise and frequent state updates. Thus, it is crucial to consider this trade-off between location privacy and quality of service of the safety application when designing and evaluating privacy schemes. In this paper, we propose a methodology to measure both the protection level of a privacy scheme and its impact on safety applications. We employ an empirical vehicle tracker to measure the effectiveness of a privacy scheme in terms of a number of confusions. We also measure its impact on a safety application by estimating the probability of correctly identifying the fundamental factors of that application using Monte Carlo analysis. Further, we propose an obfuscation privacy scheme which perturbs position and beacon frequency. Finally, we apply our methodology to evaluate the proposed scheme and compare it with the popular privacy scheme, random silent period. [less ▲]

Detailed reference viewed: 93 (0 UL)
Full Text
Peer Reviewed
See detailPOSTER: Context-adaptive user-centric privacy scheme for VANET
Emara, Karim Ahmed Awad El-Sayed UL; Woerndl, Wolfgang; Schlichter, Johann

in Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, LNICST (2015)

Vehicular adhoc network allows vehicles to exchange their information for safety and traffic efficiency. However, exchanging information may threaten the driver privacy because it includes spatiotemporal ... [more ▼]

Vehicular adhoc network allows vehicles to exchange their information for safety and traffic efficiency. However, exchanging information may threaten the driver privacy because it includes spatiotemporal information and is broadcast publicly on a periodical basis. In this paper, we propose a context-adaptive privacy scheme which lets a vehicle decide autonomously when to change its pseudonym and how long it should remain silent to ensure unlinkability. This scheme adapts dynamically based on the density of the surrounding traffic and the user privacy preferences. According to the experimental results, the proposed scheme demonstrates a significant reduction in traceability with a better quality of forward collision warning application compared with the random silent period scheme. \textcopyright Institute for Computer Sciences, Social Informatics and Telecommunications Engineering 2015. [less ▲]

Detailed reference viewed: 87 (4 UL)
Full Text
Peer Reviewed
See detailCAPS: Context-Aware Privacy Scheme for VANET Safety Applications
Emara, Karim Ahmed Awad El-Sayed UL; Woerndl, Wolfgang; Schlichter, Johann

in ACM Wisec 15 (2015)

Preserving location privacy in vehicular ad hoc networks (VANET) is an important requirement for public accep- tance of this emerging technology. Many privacy schemes concern changing pseudonyms ... [more ▼]

Preserving location privacy in vehicular ad hoc networks (VANET) is an important requirement for public accep- tance of this emerging technology. Many privacy schemes concern changing pseudonyms periodically to avoid linking messages. However, the spatiotemporal information con- tained in beacons makes vehicles traceable and the driver’s privacy breached. Therefore, the pseudonym change should be performed in a mix-context to discontinue the spatial and temporal correlation of subsequent beacons. Such mix- context is commonly accomplished by using a silence period or in predetermined locations (e.g., mix-zone). In this pa- per, we propose a location privacy scheme that lets vehicles decide when to change its pseudonym and enter a silence period and when to exit from it adaptively based on its con- text. In this scheme, a vehicle monitors the surrounding vehicles and enters silence when it finds one or more neigh- bors silent. It resumes beaconing with a new pseudonym when its actual state is likely to be mixed with the state of a silent neighbor. We evaluate this scheme against a global multi-target tracking adversary using simulated and realistic vehicle traces and compare it with the random silent period scheme. Furthermore, we evaluate the quality of service of a forward collision warning safety application to ensure its applicability in safety applications. We measure the quality of service by estimating the probability of correctly identify- ing the fundamental factors of that application using Monte Carlo analysis. [less ▲]

Detailed reference viewed: 84 (12 UL)