A Collaboratively Hidden Location Privacy Scheme for VANETs

Communication messages in vehicular ad hoc networks (VANET) can be used to locate and track vehicles. While tracking can be beneficial for vehicle navigation, it can also lead to threats on location privacy of vehicle user. In this paper, we address the problem of mitigating unauthorized tracking of vehicles based on their broadcast communications, to enhance the user location privacy in VANET. Compared to other mobile networks, VANET exhibits unique characteristics in terms of vehicular mobility constraints, application requirements such as a safety message broadcast period, and vehicular network connectivity. Based on the observed characteristics, we propose a scheme called AMOEBA, that provides location privacy by utilizing the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">group navigation of vehicles</i> . By simulating vehicular mobility in freeways and streets, the performance of the proposed scheme is evaluated under VANET application constraints and two passive adversary models. We make use of vehicular groups for anonymous access to location based service applications in VANET, for user privacy protection. The robustness of the user privacy provided is considered under various attacks.

In Vehicular Ad Hoc Networks (VANETs), a vehicle could be identified and tracked by eavesdropping its messages (e.g., beacons) by an adversary, since these messages contain personal information such as the location of the vehicle. This attack leads to threats on the user's location privacy. Frequent changing pseudonyms are accepted as a solution to protect the location privacy of users in VANETs. In this paper, we propose an efficient pseudonym changing strategy to provide location privacy in VANETs. In addition, we describe a novel tracking attack, that is, the cheating attack. To confront this attack, we develop a cheating detection mechanism. Finally, we show by simulations that the proposed scheme is effective.

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.

Although Vehicular Ad hoc NETworks (VANETs) can improve safety, efficiency and convenience in transportation, VANETs also introduce some location privacy risk by periodically broadcasting beacon message. Frequently changing pseudonyms is commonly accepted as one approach to protect location privacy in VANETs, but most changing pseudonyms schemes have disadvantages of lacking flexibility, facing with the risk of safety and inefficient, and neglect the practical implications. In this paper, we propose a novel and practical pseudonym change scheme, called CPSN. In the CPSN scheme, the minimum use time of pseudonym is introduced to guarantee routing functionality. Moreover, considering user vehicle in a real VANET being rational and selfish, we use Game theory to prove the feasibility of the CPSN scheme in reality. Finally, we investigate the performance of CPSN by simulation. The results indicate that the CPSN scheme not only provides enough location privacy protection but also satisfies the requirements of routing.

Trilateration is one of the well-known threat models to the user's location privacy in location-based apps; especially those contain highly sensitive information such as dating apps. The threat model mainly bases on the publicly shown distance from a targeted victim to the adversary to pinpoint the victim's location. As a countermeasure, most of location-based apps have already implemented the “hide distance” function, or added noise to the publicly shown distance in order to protect their user's location privacy. The effectiveness of such approaches however is still questionable. Therefore, in this paper, we investigate how the popular location-based dating apps are currently protecting their user's privacy by testing three popular GLBT-focused apps: Grindr, Jack'd, and Hornet. We found that Jack'd has the most privacy issues among the three apps. As one of our findings, we also show how the adversary can still figure out the location of a targeted victim even when the “show distance” function is disabled in Grindr. Without using sophisticated hacking techniques, our proposed model (called colluding-trilateration) is still very effective and efficient at locating the targeted victim, and of course in a so-called “legal” manner, because we only utilize the information that can be obtained just as same as any other ordinary user. In case of Hornet, although it has adopted location obfuscation in its system, we were not only able to discover its noise-adding pattern by conducting empirical analysis, but also able to apply the colluding trilateration used in Grindr to locate the targeted victim regardless of the location obfuscation. Our study thus raises an urgent alarm to the users of those location-based apps in general and GLBT-focused dating apps in particular about their privacy. Finally, the paper concludes by suggesting some possible solutions from the viewpoints of both the LBS provider and the user considering the implementation cost and the trade-off of utility.

Due to the dire consequences of privacy abuse in vehicular ad hoc network (VANET), a number of mechanisms have been put forth to conditionally preserve the user and location privacy. To date, multiple pseudonymous approach is regarded as one of the best effective solutions where every node uses multiple temporary pseudonyms. However, recently it has been found out that even multiple pseudonyms could be linked to each other and to a single node thereby jeopardizing the privacy. Therefore in this paper, we propose a novel identity exchange-based approach to preserve user privacy in VANET where a node exchanges its pseudonyms with the neighbors and uses both its own and neighbors' pseudonym randomly to preserve privacy. Additionally the revocation of the immediate user of the pseudonym is made possible through an efficient revocation mechanism. Moreover the pseudonym exchange is realized through covert communication where a side channel is used to establish a covert communication path between the exchanging nodes, based on the scheduled beacons. Our proposed scheme is secure, robust, and it preserves privacy through the existing beacon infrastructure.

In vehicular ad hoc networks (VANETs), the malicious messages and tampered messages threat other drivers' life or confuse the traffic order possibly. The anonymity has to be traceable when the law enforcement authority wants to figure out the accountabilities about the anonymity. We describe the problem that characterizes the privacy of VANETs and proposes a new anonymous key mechanism with a system architecture based on bilinear paring and elliptic curve cryptography which adapts to VANETs. The anonymous key pair generated by proposed anonymous key mechanism can realize basic security requirements, and protect identity privacy and location privacy in VANETs communication. The data storage cost can also be decreased when the numbers of node grows quickly.

Location privacy plays an important role in Vehicular Ad Hoc Networks (VANETs). Pseudonym is normally used to preserve location privacy, which can meet the requirements of both privacy and security. When the same pseudonym is constantly used for a vehicle, the adversary can easily track it. To improve location privacy, a lot of pseudonym change schemes have been proposed. However, the tracker can match vehicles by the beacon message when it has found that the pseudonym is changed. Besides, every vehicle must hold lots of pseudonyms to change in these schemes. In this paper, we propose a trigger-based pseudonym exchange scheme, which aims to thwart to track vehicle from the sending beacons and reduce the storage consumption. We propose two trigger-based algorithms to decide when and how a vehicle exchange pseudonym with others. To evaluate the performance of our scheme, we conduct the probability of exchanging pseudonym in a road segment and a traffic intersection, and measure the tracking percent by an empirical tracker. The simulation results show that our scheme is resilient to confuse the tracker efficiently.

Vehicular ad hoc networks (VANETs) are a subset of mobile ad hoc networks that provide communication services between nearby vehicles and also between vehicles and roadside infrastructure. These networks improve road safety and accident prevention and provide entertainment for passengers of vehicles. Due to the characteristics of VANET such as self-organization, dynamic nature and fast-moving vehicles, routing in this network is a considerable challenge. Swarm intelligence algorithms (nature-inspired) such as ant colony optimization (ACO) have been proposed for developing routing protocols in VANETs. In this paper, we propose an enhanced framework for ACO protocol based on fuzzy logic for VANETs. To indicate the effectiveness and performance of our proposed protocol, the network simulator NS-2 is used for simulation. The simulation results demonstrate that our proposed protocol achieves high data packet delivery ratio and low end-to-end delay compared to traditional routing algorithms such as ACO and ad hoc on-demand distance vector (AODV).

A Vehicular Ad hoc NETwork (VANET) is a type of mobile Peer-To-Peer wireless network that allows providing communication among nearby vehicles and between vehicles and nearby fixed roadside equipment. The lack of centralized infrastructure, high node mobility and increasing number of vehicles in VANETs result in several problems discussed in this paper, such as interrupting connections, difficult routing, security of communications and scalability. Existing system for VANET communication is proved to have several drawbacks. We have proposed a mechanism in order to provide secure and efficient communication in VANET environment. We overcome the drawbacks of the existing system by using Malicious Vehicular Analyzer algorithm and Elliptic Curve Cryptography (ECC). Using these algorithms, malicious messages are identified. It also detects the accident and other problems in the path of the vehicles. Elliptic Curve Cryptography (ECC) algorithm is used for stronger security during communication.

Vehicular ad hoc network (VANET) is a mobile ad hoc network with a dynamic property; the vehicles possess high mobility and undergo fast topology changes. This special type of mobile ad hoc network is a popular topic of research. Owing to the specific features of VANETs, unique routing protocols are required for short-range, high-speed communication among nearby vehicles. In this study, we propose a new opportunistic routing scheme based on the timed bargaining game. In order to dynamically adapt to the current VANET situation, the proposed scheme effectively formulates the opportunistic routing mechanism as an iterative bargaining model with a timed learning approach. Based on a simulation study, it is confirmed that the proposed scheme can achieve better performance than other existing schemes in diverse VANET environments.

Vehicular Ad hoc Network (VANET) plays a significant role in safety communication and commercial applications. Applications necessitate to track the location of vehicles, have a strong impact on location privacy and security. Ensuring the correctness of location information is essential without it being disclosed to other vehicles. Conventionally, a privacy preservation mechanism disseminates anonymous beacons for providing location based services to the vehicles and it is verified by the Location Server (LS). In VANET, it is crucial to develop a technique that provides security and privacy with minimum overhead. This study proposes a lightweight mechanism called as Preservation of Location Privacy through Anonymous Beacon (PLPAB) that provides location-based services to the users in a secured manner. Initially at the time of registration, a vehicle receives a triplet from LS. The triplet has a short term symmetric key for beacon encryption and decryption and it generates two random integers to evaluate mysterious time-dependent value shared between LS and vehicle. PLPAB includes two mechanisms such as anonymous beacon generation and location verification. In beacon generation, the vehicles broadcast an anonymous beacon at a specific interval for providing the secure location information. Instead of generating the beacon at all the time, it enables a vehicle to generate a beacon adapting to its mobility. Thus, it reduces unnecessary beacon generation, resulting in less overhead. In location verification, LS verifies the claimed location in the beacon by determining the inference of location using signal strength and speed of the beacon originator. The simulation results show that the PLPAB system achieves and preserves a higher level of location privacy on vehicles and is more resilient to attacks when compared to the existing A-VIP scheme.

For improving the traffic safety in intelligent transportation systems, vehicles that are formed by Vehicular Ad-hoc Networks (VANETs) conventionally disseminate warning messages to their nearby vehicles as soon as a dangerous situation occurs. However, the major challenge in VANETs is to develop an efficient data dissemination protocol for tackling the broadcast storm and network partition problems. In this paper, we propose an Adaptive Beacon-based Data Dissemination (ABDDis) scheme to deal with these problems using only local one-hop neighbor information. The ABDDis scheme features a novel mechanism to adaptively adjust the beacon interval to reduce the channel load while maintaining the correct information about nearby vehicles. Additionally, a novel store-carry-forward (SCF) mechanism is proposed to overcome the network partition problem. The performance of the ABDDis scheme is evaluated in the Veins simulation framework that provides a bidirectional coupling between the network simulator OMNeT++ and the traffic simulator SUMO. The simulation result shows that the ABDDis scheme significantly mitigates the broadcast storm compared to other schemes and maintains a good coverage across various traffic densities. Moreover, the ABDDis scheme shows its robustness by being able to tolerate reasonable GPS drift.

Preserving location privacy is increasingly an essential concern in Vehicular Adhoc Networks (VANETs). Vehicles broadcast beacon messages in an open form that contains information including vehicle identity, speed, location, and other headings. An adversary may track the various locations visited by a vehicle using sensitive information transmitted in beacons such as vehicle identity and location. By matching the vehicle identity used in beacon messages at various locations, an adversary learns the location history of a vehicle. This compromises the privacy of the vehicle driver. In existing research work, pseudonyms are used in place of the actual vehicle identity in the beacons. Pseudonyms should be changed regularly to safeguard the location privacy of vehicles. However, applying simple change in pseudonyms does not always provide location privacy. Existing schemes based on mix zones operate efficiently in higher traffic environments but fail to provide privacy in lower vehicle traffic densities. In this paper, we take the problem of location privacy in diverse vehicle traffic densities. We propose a new Crowd-based Mix Context (CMC) privacy scheme that provides location privacy as well as identity protection in various vehicle traffic densities. The pseudonym changing process utilizes context information of road such as speed, direction and the number of neighbors in transmission range for the anonymisation of vehicles, adaptively updating pseudonyms based on the number of a vehicle neighbors in the vicinity. We conduct formal modeling and specification of the proposed scheme using High-Level Petri Nets (HPLN). Simulation results validate the effectiveness of CMC in terms of location anonymisation, the probability of vehicle traceability, computation time (cost) and effect on vehicular applications.

Providing safety applications is one of the principal motivations behind deploying vehicular ad hoc networks (VANETs). These applications require fair (i.e., all vehicles get equal fraction of time allocation for their transmissions) and reliable (i.e., transmissions are received with high probably by the intended receivers) broadcasting of relevant driving data. In this paper we compare the performance of IEEE 802.11p and a recent time-division based medium access control protocol, Dynamic Channel Reservation (DCR) in realistic high-density traffic scenarios. We focus on the communication requirements that allow vehicles to receive safety messages well enough in advance to warn the driver in a timely manner and avoid crashes. We observe performance degradation in both schemes as we examine them in congested environments. In such scenarios, in 802.11p, broadcast reliability decreases, while in DCR, some vehicles face starvation, thus the fairness requirement is not met. In order to avoid this situation, we propose a modified version of DCR, fDCR, in which time channels can be occupied by several vehicles, thus fostering a fair channel reservation scheme. Our channel reservation scheme is designed in a way that minimizes packet collisions due to a transmission, in receivers which are close to that transmitter. Furthermore, to enhance the probability of reception in nearby vehicles, which is one of the main communication requirements of safety applications, we propose a low-overhead transmission power control scheme. Our fully distributed power control scheme leverages on the extra transmitted information by DCR to estimate the number of vehicles in its transmission range, and accordingly adjust the transmission power. Experimental results show significant performance gains in cases of both cross-through and non-cross-through traffic for our proposed scheme in comparison with 802.11p and DCR.