Dependability in wireless networks: can we rely on WiFi?

WiFi - short for "wireless fidelity" - is the commercial name for the 802.11 products that have flooded the corporate wireless local area network (WLAN) market and are becoming rapidly ingrained in our daily lives via public hotspots and digital home networks. Authentication and confidentiality are crucial issues for corporate WiFi use, but privacy and availability tend to dominate pervasive usage. However, because a technology's dependability requirements are proportional to its pervasiveness, newer applications mandate a deeper understanding of how much we can rely on WiFi and its security promises. In this article, we present an overview of WiFi vulnerabilities and investigate their proximate and ultimate origins. The intended goal is to provide a foundation to discuss WiFi dependability and its impact on current and future usage scenarios. Although a wireless network's overall security depends on the network stack to the application layer, this article focuses on specific vulnerabilities at the physical (PHY) and data (MAC) layers of 802.11 network

Impact of Vehicular Communications Security on Transportation Safety

Transportation safety, one of the main driving forces of the development of vehicular communication (VC) systems, relies on high-rate safety messaging (beaconing). At the same time, there is consensus among authorities, industry, and academia on the need to secure VC systems. With specific proposals in the literature, a critical question must be answered: can secure VC systems be practical and satisfy the requirements of safety applications, in spite of the significant communication and processing overhead and other restrictions security and privacy-enhancing mechanisms impose? To answer this question, we investigate in this paper the following three dimensions for secure and privacy-enhancing VC schemes: the reliability of communication, the processing overhead at each node, and the impact on a safety application. The results indicate that with the appropriate system design, including sufficiently high processing power, applications enabled by secure VC can be in practice as effective as those enabled by unsecured VC

On the Performance of Secure Vehicular Communication Systems

Vehicular communication (VC) systems are developed primarily to enhance transportation safety and efficiency. Vehicle-to-vehicle communication, in particular frequent cooperative awareness messages or safety beacons, have been considered over the past years as a main approach. Meanwhile, the need to provide security and safeguard the users privacy have been well understood, and security architectures for VC systems have been proposed. Although technical approaches to secure VC have several commonalities and a consensus has formed, there are critical questions that have remained largely unanswered: Are proposed security and privacy schemes practical? Can the secured VC systems support the VC-enabled applications as effectively as unsecured VC would? How should security be designed so that its integration into a VC system has the least impact on the system performance? In this paper, we provide answers to these questions, investigating the joint effect of a set of system parameters and components. We consider the stateof-the-art approach in secure VC, and we evaluate analytically and through simulations interdependencies among components and system characteristics. Overall, we identify the key design choices to deploy efficient and effective secure VC

A wireless distributed intrusion detection system and a new attack model

Denial-of-Service attacks, and jamming in particular, are a threat to wireless networks because they are at the same time easy to mount and difficult to detect and stop. We propose a distributed intrusion detection system in which each node monitors the traffic flow on the network and collects relevant statistics about it. By combining each node’s view we are able to tell if (and which type of) an attack happened or if the channel is just saturated. However, this system opens the possibility for misuse. We discuss the impact of the misuse on the system and the best strategies for each actor.

On the performance of secure vehicular communication systems

Vehicular communication (VC) systems are being developed primarily to enhance transportation safety and efficiency. Vehicle-to-vehicle communication, in particular, frequent cooperative awareness messages or safety beacons, has been considered over the past years as a main approach. Meanwhile, the need to provide security and to safeguard users' privacy is well understood, and security architectures for VC systems have been proposed. Although technical approaches to secure VC have several commonalities and a consensus has formed, there are critical questions that have remained largely unanswered: Are the proposed security and privacy schemes practical? Can the secured VC systems support the VC-enabled applications as effectively as unsecured VC would? How should security be designed so that its integration into a VC system has a limited effect on the system's performance? In this paper, we provide answers to these questions, investigating the joint effect of a set of system parameters and components. We consider the state-of-the-art approach in secure VC, and we evaluate analytically and through simulations the interdependencies among components and system characteristics. Overall, we identify key design choices for the deployment of efficient, effective, and secure VC systems

Efficient and robust pseudonymous authentication in VANET

Effective and robust operations, as well as security and privacy are critical for the deployment of vehicular ad hoc networks (VANETs). Efficient and easy-to-manage security and privacy-enhancing mechanisms are essential for the wide-spread adoption of the VANET technology. In this paper, we are concerned with this problem; and in particular, how to achieve efficient and robust pseudonym-based authentication. We design mechanisms that reduce the security overhead for safety beaconing, and retain robustness for transportation safety, even in adverse network settings. Moreover, we show how to enhance the availability and usability of privacy-enhancing VANET mechanisms: Our proposal enables vehicle on-board units to generate their own pseudonyms, without affecting the system security

Correlation of Macular Focal Electroretinogram with Ellipsoid Zone Extension in Stargardt Disease

Stargardt disease (STGD1) is the most common cause of inherited juvenile macular degeneration. This disease is characterized by a progressive accumulation of lipofuscin in the outer retina and subsequent loss of photoreceptors and retinal pigment epithelium. The aim of this study was to evaluate the relationship between cone photoreceptor function and structure in STGD1. Macular function was assessed by visual acuity measurement and focal electroretinogram (FERG) recording while spectral domain optical coherence tomography (SD-OCT) imaging was performed to evaluate the integrity of photoreceptors. FERG amplitude was significantly reduced in patients with Stargardt disease (p < 0.0001). The amplitude of FERG showed a negative relationship with interruption of ellipsoid zone (EZ) (R2 = 0.54, p < 0.0001) and a positive correlation with average macular thickness (AMT). Conversely, visual acuity was only weakly correlated with central macular thickness (CMT) (R2 = 0.12, p = 0.04). In conclusion, this study demonstrates that FERG amplitude is a reliable indicator of macular cone function while visual acuity reflects the activity of the foveal region. A precise assessment of macular cone function by FERG recording may be useful to monitor the progression of STGD1 and to select the optimal candidates to include in future clinical trials to treat this disease