  Pairwise key establishment is one of the fundamental security services in
sensor networks which enables sensor nodes in a sensor network to communicate
securely with each other using cryptographic techniques. It is not feasible to
apply traditional public key management techniques in resource-constrained
sensor nodes, and also because the sensor nodes are vulnerable to physical
capture. In this paper, we introduce a new scheme called the identity based key
pre-distribution using a pseudo random function (IBPRF), which has better
trade-off between communication overhead, network connectivity and resilience
against node capture compared to the other key pre-distribution schemes. Our
scheme can be easily adapted in mobile sensor networks. This scheme supports
the addition of new sensor nodes after the initial deployment and also works
for any deployment topology. In addition, we propose an improved version of our
scheme to support large sensor networks.
