Increasing Base-Station Anonymity in Wireless Ad-hoc and Sensor Networks

In many applications of ad-hoc networks, most traffic is targeted to few nodes. For example, in a surveillance network the gathered intelligence data about criminal activities flow towards a field commander or an in-situ BS. Such a network operation model makes BS a critical asset for these applications. An adversary can nullify the value of a network by disrupting or physically damaging the BS, without targeting individual data sources. BS failure can also cause a loss of important data. Therefore, concealing the location and role of BS is of utmost importance for maintaining a robust network operation. Packet encryption does not achieve BS anonymity since an adversary can intercept the individual wireless transmissions and employ traffic analysis techniques to follow the data paths without knowing the content of intercepted traffic. Since all active routes end at BS, the adversary may be able to determine BSs location and launch targeted attacks. Similarly, camouflaging or hiding the BS does not provide protection when its location is unveiled via traffic analysis. Employing spread spectrum signaling methods is not a sufficient countermeasure as adversaries are becoming more advanced and equipped with sophisticated intercept technologies. In addition, signal spreading reduces rather than eliminates the prospect of transmission detection. Published studies have indicated that there is no silver-bullet solution for ensuring BS anonymity. To the best of our knowledge, there is no comprehensive multi-layer solution that adopts multiple strategies and adaptively employs countermeasures. This proposal promotes investigating the various anonymity attacks, defining metrics, and developing effective countermeasures along with guidelines on what techniques to employ for a particular application scenario. The trade-off between BS anonymity and associated network overhead is considered for each countermeasure. The key technical contributions of the proposed research are: (1) to define appropriate metrics to quantitatively assess BS anonymity; (2) to enumerate various models of anonymity attacks -- An adversary can eavesdrop on the entire network by setting up antennas to intercept the transmitted packets within the deployment area, or can be in-situ and mobile to stimulate the network traffic by intentionally triggering events that generate data traffic; (3) to develop cross-layer techniques for countering traffic analysis and concealing the location and role of the BS; (4) to build a prototype system for validating the proposed research and enabling hands-on experience for our students. This project will contribute to the goal of designing robust networks for mission-critical applications that can maintain the anonymity of its important assets and avert adversary attacks. Our proposed research can boost the effectiveness of many civil and military applications of national and international interest. Examples of these applications include first responder, border patrol, and security surveillance. The outcome of this project is of great importance to the Kingdom as it will help in achieving the Kingdom vision in building a knowledge society. Hence, the developed methods, in this project, will help in creating new businesses that will help in diversifying the national income resources.