Several Security Issues In Wireless Ad Hoc Networks

Driven by commercial interests, several new research branches appear in wireless ad hoc networks. We extend our work on several hot security-related topics in Wireless Sensor Networks and Vehicular Ad hoc Networks.The first part of our work is concerned with key management and deployment strategies in Wireless Sensor Networks. Due to the resource constraints, key management has been a quite challenging problem in Wireless Sensor Networks. We propose three deployment models and introduce the corresponding key management scheme. In our scheme, the deployment field is divided into grids, while sensor nodes are divided into two types, i.e. inner nodes and gateway nodes. When combined with an appropriate key management scheme, our scheme can effectively enhance the connectivity between inter-grid nodes and the security resilience. Our scheme also has the potential to reduce the key-allocation work during the pre-deployment phase, significantly improving the deployment flexibility. Our contribution in this work focuses on the attempt to improve system security and flexibility from the perspective of deployment models, whereas previous schemes are proposed from the perspective of key management.The second part of our work is concerning selectively forwarding attacks in Wireless Sensor Networks. We propose an intrusion detection scheme for this type of attack. In our scheme, we use several techniques to improving the detection performance, including: random checkpoint selection, k-covered acknowledgement, etc. Every source node, in our scheme, has the capability to accumulate alert messages from intermediate nodes. This desirable feature empowers source nodes to have the potential to perform detection and take responses, even when the base station is deafened during attacks. The contribution in this work is that we propose a checkpoint-based acknowledgement scheme for detecting selective forwarding attacks. To our knowledge, little work concerning the same problem has been made before.The third part of our work focuses on Sybil attacks in Vehicular Ad hoc Networks. We propose a detection scheme based on the analysis of signal strength distribution. Unlike traditional position verification techniques, which reply on specific hardware, our scheme tries to estimate the node physical position and then verify whether its claimed position is consistent with its physical position. Our signal strength approachis simple but powerful. Most of existing radio components such as MICA2 nodes, 802.11, Blue Tooth, support RSSI (Received Signal Strength Indicator) very well, making our scheme applicable to Vehicular Networks. The contribution of this work is the attempt to verify node position based on signal strength analysis. This technique would be inappropriate for traditional sensor networks and has not been investigated before. However, the unique properties of Vehicular Network present new opportunities to use this technique to our advantage.