Anonymous Authenticated Car-to-X Communication

Two current trends in the automotive industry are the increasing number of connected vehicles and automated driving. The former enables the use of different applications within the vehicle. These applications might be restricted to vehicles with certain features such as manufacturer or model. To enable automated driving, the vehicle needs information about the road ahead. This information might be provided by an application. In order to keep the street information up to date connected vehicles share their sensor data. This data is then aggregated on a central server. Furthermore, it has a restricted spatial and temporal validity. Therefore, the vehicles also need to provide the corresponding time and position information. When reporting position data, it is possible, for example, to generate movement profiles or to identify sensitive locations. Hence, it is critical which information different applications reveal about the corresponding vehicles. Therefore, in this thesis we propose four different schemes which restrict the information applications can obtain from vehicles. The first scheme addresses the problem how a vehicle can authenticate itself privacy preserving based on attributes at an application without revealing all its attributes. The second scheme provides a solution for the question how two vehicles can authenticate each other for an application and exchange confidential data without disclosing their identity. The third scheme obfuscates the identity of a vehicle while sharing sensor data with a central server. The fourth scheme is related to the question how data can be distributed by a central server to all vehicles equipped with a particular application and located within a certain area without tracking the vehicles and knowing their subscribed applications. In addition, we outline how these schemes can be combined. We demonstrate that each scheme is practical by presenting prototype implementations. Additionally, we simulate the second and third scheme in order to assess the impact on the vehicles privacy

Performance improvement in geographic routing for vehicular Ad Hoc networks

Geographic routing is one of the most investigated themes by researchers for reliable and efficient dissemination of information in Vehicular Ad Hoc Networks (VANETs). Recently, different Geographic Distance Routing (GEDIR) protocols have been suggested in the literature. These protocols focus on reducing the forwarding region towards destination to select the Next Hop Vehicles (NHV). Most of these protocols suffer from the problem of elevated one-hop link disconnection, high end-to-end delay and low throughput even at normal vehicle speed in high vehicle density environment. This paper proposes a Geographic Distance Routing protocol based on Segment vehicle, Link quality and Degree of connectivity (SLD-GEDIR). The protocol selects a reliable NHV using the criteria segment vehicles, one-hop link quality and degree of connectivity. The proposed protocol has been simulated in NS-2 and its performance has been compared with the state-of-the-art protocols: P-GEDIR, J-GEDIR and V-GEDIR. The empirical results clearly reveal that SLD-GEDIR has lower link disconnection and end-to-end delay, and higher throughput as compared to the state-of-the-art protocols. It should be noted that the performance of the proposed protocol is preserved irrespective of vehicle density and spee

A Mini Review of Peer-to-Peer (P2P) for Vehicular Communication

In recent times, peer-to-peer (P2P) has evolved, where it leverages the capability to scale compared to server-based networks. Consequently, P2P has appeared to be the future distributed systems in emerging several applications. P2P is actually a disruptive technology for setting up applications that scale to numerous concurrent individuals. Thus, in a P2P distributed system, individuals become themselves as peers through contributing, sharing, and managing the resources in a network. In this paper, P2P for vehicular communication is explored. A comprehensive of the functioning concept of both P2P along with vehicular communication is examined. In addition, the advantages are furthermore conversed for a far better understanding on the implementation

Towards reliable geographic broadcasting in vehicular networks

In Vehicular ad hoc Networks (VANETs), safety-related messages are broadcasted amongst cars, helping to improve drivers' awareness of the road situation. VANETs’ reliability are highly affected by channel contention. This thesis first addresses the issue of channel use efficiency in geographical broadcasts (geocasts). Constant connectivity changes inside a VANET make the existing routing algorithms unsuitable. This thesis presents a geocast algorithm that uses a metric to estimate the ratio of useful to useless packet received. Simulations showed that this algorithm is more channel-efficient than the farthest-first strategy. It also exposes a parameter, allowing it to adapt to channel load. Second, this thesis presents a method of estimating channel load for providing feedback to moderate the offered load. A theoretical model showing the relationship between channel load and the idle time between transmissions is presented and used to estimate channel contention. Unsaturated stations on the network were shown to have small but observable effects on this relationship. In simulations, channel estimators based on this model show higher accuracy and faster convergence time than by observing packet collisions. These estimators are also less affected by unsaturated stations than by observing packet collisions. Third, this thesis couples the channel estimator to the geocast algorithm, producing a closed-loop load-reactive system that allows geocasts to adapt to instantaneous channel conditions. Simulations showed that this system is not only shown to be more efficient in channel use and be able to adapt to channel contention, but is also able to self-correct suboptimal retransmission decisions. Finally, this thesis demonstrates that all tested network simulators exhibit unexpected behaviours when simulating broadcasts. This thesis describes in depth the error in ns-3, leading to a set of workarounds that allows results from most versions of ns-3 to be interpreted correctly

Efficient and secure delivery of area-persistent safety messages in vehicular ad hoc networks

In this thesis, we propose an adaptive mechanism for the delivery of safety messages in vehicular networks in an authenticated and privacy-preserving manner. The traditional approach to message delivery for driving safety applications running on vehicular ad hoc networks (VANETs) has been to increase redundancy, often at the sake of other applications running on the network. We argue that this approach does not accommodate the traffic conditions of crowded cities like İstanbul, and present a probabilistic method for the dissemination of area-persistent safety messages in infrastructureless vehicular networks that dynamically adapts itself to changing road conditions. Our proposed protocol utilizes short group signatures for privacy-preserving authentication, and keyed-Hash Message Authentication Codes (HMACs) with one-way hash chains to decrease computational load on Onboard Units (OBUs). We also introduce a vehicular mobility model that creates scenarios of high-speed traffic on crowded highways based on realistic assumptions, and measure the performance of the proposed protocol using scenarios generated by this model. Our simulations show that the proposed method decreases network traffic by up to 82% and shortens delivery delays by up to 13% when compared to non-probabilistic methods in highway scenarios with medium to high vehicle density

Privacy-preserving Cooperative Services for Smart Traffic

Communication technology and the increasing intelligence of things enable new qualities of cooperation. However, it is often unclear how complex functionality can be realized in a reliable and abuse-resistant manner without harming users\u27 privacy in the face of strong adversaries. This thesis focuses on three functional building blocks that are especially challenging in this respect: cooperative planning, geographic addressing and the decentralized provision of pseudonymous identifiers

Routing in mobile Ad Hoc Networks

A Mobile Ad Hoc Network (MANET) is built on the fly where a number of wireless mobile nodes work in cooperation without the engagement of any centralized access point or any fixed infrastructure. Two nodes in such a network can communicate in a bidirectional manner if and only if the distance between them is at most the minimum of their transmission ranges. When a node wants to communicate with a node outside its transmission range, a multihop routing strategy is used which involves some intermediate nodes. Because of the movements of nodes, there is a constant possibility of topology change in MANET. Considering this unique aspect of MANET, a number of routing protocols have been proposed so far. This chapter gives an overview of the past, current, and future research areas for routing in MANET. In this chapter we will learn about the following things: - The preliminaries of mobile ad hoc network - The challenges for routing in MANET - Expected properties of a MANET routing protocol - Categories of routing protocols for MANET - Major routing protocols for MANET - Criteria for performance comparison of the routing protocols for MANET - Achievements and future research directions - Expectations and realit