Vehicular Ad-hoc Networks (VANETs), which are a subclass of Mobile Ad-hoc Networks (MANETs), received a widespread attention during the last decades. With these promising set of safety applications, which are the main reason why they were developed, VANETs are considered as a tremendous support for the Intelligent Transportation Systems (ITS). However, several key issues remain to be solved before VANET becomes fully applicable; one of them being privacy preservation. To fulfill safety-requirements in VANETs, the vehicle needs to broadcast its status wirelessly. Consequently, any adversary can hear the broadcast messages at the aim of analyzing them, identifying, tracking and generating profile of his target. In other words, privacy of individuals may be seriously breached in VANETs if no safety measures were been taken. Using pseudonyms instead of the real identities of individuals, and changing them periodically during the communication is a promising solution for such crucial problems. There is a significant body of research work addressing this issue and a lot of researchers proposed various privacy protections basing on pseudonym change strategies. In this survey paper, we present an introduction to the privacy problem and give a recent and detailed state of the art of the different suggested pseudonym change strategies and approaches. We also propose a novel taxonomy to classify these strategies to diverse concepts. Finally, we discuss, give future directions and open issues and mention some of the observations that lead to better identify this problem for better future strategies.

The internet of vehicles (IoV) is getting a considerable amount of attention from different research parties. IoV aims at enhancing the driving experience with its wide range of applications varying from safety, road management to entertainment; however, some of such applications bring severe security and privacy issues; identity exposing, and location tracking are good examples. By enabling vehicles to send their statuses to themselves via beacon messages, this creates an environmental awareness for safety purposes but also exposes them to the aforementioned attacks. A lot of work has been done to mitigate the effect of such attacks but still does not provide a holistic solution. In this article, which is an extension to a prior work, the authors investigate the effects of changing the transmission range while sending beacons on the achieved level of location privacy based on two location privacy schemes: SLOW and CAPS. The authors use additional privacy metrics in addition to comparing the strategies in some well-known security attacks. The outcomes confirm the feasibility of using such a mechanism.

Vehicular Ad-hoc Networks (VANETs) are in the rollout phase. VANETs are mainly instantiated to mitigate the number of crashes and fatalities by enabling an intensive beaconing that contains the fine-grained location of each vehicle at the aim of creating environmental awareness for safety purposes. However, this frequent location information may be obtained by adversaries after overhearing the beacons; giving an unauthenticated entity(s) the ability to monitor the vehicles' whereabouts in a region of interest. A lot of schemes to protect location privacy were proposed. In this paper, we provide an enhancement of a set of schemes by allowing vehicles to adjust their beacon transmission range to conditionally avoid tracking. For the best of our knowledge, and excluding the scopes other than location privacy in VANETs, this is the first evaluation of transmission adjustment influence on the achieved location privacy. We made an evaluation of this feature's performances after integrating it into some of the well-known strategies, namely: SLOW and CAPS, against (1) the achieved location privacy using the traceability metric and (2) the network performances. The results show the beneficial usability of such a feature.

The main purpose of designing Vehicular Ad-hoc Networks (VANETs) is to achieve safety by periodically broadcasting the vehicle's coordinates with a high precision. This advantage brings a threat represented in the possible tracking and identification of the vehicles. A possible solution is to use pseudonyms instead of real identities. However, even by changing pseudonyms, the vehicle can still be tracked if the adversary has knowledge about the potential start and end points of a particular driver who has social interactions (e.g., with neighbors) which introduces the concept of Vehicular Social Networks (VSNs). In this work we propose a location privacy scheme, namely: Extreme Points Privacy (EPP) for trips and home identification in VSNs by exploiting the nature of the end points that are common between many VSN users bringing the option to create shared zones to anonymize these users. An analytical study accompanied by a simulation using the realistic vehicular traffic mobility generator SUMO are presented to show the effectiveness of the proposed scheme.

The main purpose of designing vehicular ad-hoc networks (VANETs) is to achieve safety by periodically broadcasting the vehicle's coordinates with a high precision. This advantage brings a threat represented in the possible tracking and identification of the vehicles. A possible solution is to use and change pseudonyms. However, even by changing pseudonyms, the vehicle could still be tracked if the adversary has a prior knowledge about the potential start and end points of a particular driver who has social interactions (e.g., with neighbors) which introduces the concept of vehicular social networks (VSNs). This article extends the authors previous work, namely: “EPP Extreme Points Privacy for Trips and Home Identification in Vehicular Social Networks,” which exploits the nature of the end points that are common between VSN users in order to create shared zones to anonymize them. The extension is represented by (a) the evaluation of the enjoyed location privacy of VSN users after quitting the district in addition to (b) detailing the used environment during the evaluation.