Countermeasures Against Traffic Analysis Attacks in Wireless Sensor Networks ; CU-CS-987-04

Wireless sensor networks are often constructed as asymmetric networks comprised of a large number of small, resource-constrained sensor nodes and a small number of relatively powerful base stations. A base station is vulnerable as a central point of failure in such networks. Typical packet traffic in a sensor network reveals pronounced patterns that allow an adversary analyzing packet traffic to deduce the location of a base station, which can then be disabled or destroyed. This paper investigates multiple antitraffic analysis techniques aimed at disguising the location of a base station. First, a degree of randomness is introduced in the multi-hop path a packet takes from a sensor node to a base station. Second, random fake paths are introduced to confuse an adversary from tracking a packet as it moves towards a base station. Finally, multiple, random areas of high communication activity are created to deceive an adversary as to the true location of the base station. The paper evaluates these techniques analytically and via simulation using three evaluation criteria: total entropy of the network, total energy consumed, and the ability to guard against heuristic-based techniques to locate a base station.