In vehicular networks (VN), the response time is critical, whereas, an autonomous and efficient way of preventing hazardous situations on roads plays an important role in the successful deployment of the system. Trust or reputation models often need to be integrated with inter-vehicle communication protocols in use to avoid selfish or malicious behavior by the vehicles exploiting the system. Existing trust and reputation models for VNs lack the capability of fast and accurate trust management suitable for the ephemeral association of vehicles. In this paper, we design an augmented trust model for VNs by assigning each vehicle a long term trust value. Our model eliminates the overhead of repeated bootstrapping and ensures accountability of the vehicles for incident reporting and other critical actions. The two main features of our framework, viz. a three- party authentication and privacy protocol, and a trust propagation model, both of which are crucial for a successful deployment of VNs, can also be used in any generic security application.

We present a class of Minimum Cost Blocking (MCB) problems in Wireless Mesh Networks (WMNs) with multi-path routing protocols. We establish the provable superiority of multi-path routing protocols over conventional protocols against blocking, node-isolation and network-partitioning type attacks. In our attack model, an adversary is considered successful if he is able to capture/isolate a subset of nodes such that no more than a certain amount of traffic from source nodes reaches the gateways. Two scenarios, viz. (a) low mobility for network nodes, and (b) high degree of node mobility, are evaluated. Scenario (a) is proven to be NP-hard and scenario (b) is proven to be #P-hard for the adversary to realize the goal. Further, several approximation algorithms are presented which show that even in the best case scenario it is at least exponentially hard for the adversary to optimally succeed in such blocking-type attacks. These results are verified through simulations which demonstrate the robustness of multi-path routing protocols against such attacks. To the best of our knowledge, this is the first work that theoretically evaluates the attack-resiliency and performance of multi-path protocols with network node mobility.

Malware propagation in social networks is a potential risk that has not been well-studied yet as there are no formal threat models for social networks. In this paper we investigate the vulnerability and cost of spreading malware via Twitter. Towards this end we present three specific attack scenarios targeted for Twitter and systematically analyze the cost of staging each of these attacks. Our analysis presents the first step for understanding the threats on the security of a class of social networks. We identify the attack related parameters and verify these parameters by testing the attack on a Net Logo based simulator. Our analysis indicates that the cost of staging attacks to infect users of Twitter is low and that the proposed attack scenarios are plausible. Further, even with a low degree of connectivity and a low probability of clicking links, Twitter and its structure can be exploited by such attacks to infect many users with malware.

We present a practical plant-and-play wireless sensor network system for entry-exit monitoring. Our system is easily configurable and robust, making it feasible to be deployed in a wide range of entry-exit monitoring applications. At the core of our system lies a novel MAC protocol that is self-synchronizing. Notably, our MAC protocol allows the nodes to maintain a very low duty cycle (the radios are in sleep mode 100% of the time in the absence of detections), while also enabling quick synchronization of the nodes (when needed) for a consistent classification of entry or exit events. We have deployed this system for monitoring a faculty parking lot at our university and integrated it with an SMS notification system to provide information on the availability of parking spots on demand. We present the parking lot occupancy trends obtained through this deployment and discuss some of the reliability issues encountered.