Key Predistribution in Wireless Sensor Networks When Sensors Are Within Communication Range

Wireless networks are more vulnerable to security threats than wired networks. Since sensors are resource constrained, the use of traditional cryptographic key management techniques is not practical. Hence keys are distributed in sensor nodes prior to their deployment. This method, called key predistribution, was investigated recently in a number of studies. This chapter restricts the discussion to single-hop networks, where any two sensors are within communication range of each other. The goal is to enable any two sensor nodes to exchange information using their common key, so that other sensors, or an adversary, are unable to decode the message. If two sensor nodes do not share a common key then a path between them, via other sensor nodes, is established, with sensors on the path being able to decode a message and forward it encrypted with a new key. We describe different types of key predistribution schemes for single-hop networks and discuss their merits and demerits in terms of resiliency (impact of node compromises), scalability, connectivity, and memory, computation, and communication resources. Shared-key discovery process should minimize the use of communication bandwidth. We also discuss the identification of compromised nodes and revocation techniques.