A pairwise key predistribution scheme for wireless sensor networks

TLDR

Wireless sensor networks require secure message encryption and authentication, but key agreement is difficult due to limited resources, making traditional public‑key schemes impractical. This work introduces a framework for evaluating key predistribution schemes and presents a new pairwise key predistribution method that markedly enhances network resilience. The proposed scheme assigns secret keys to node pairs in a memory‑efficient manner, and the authors analyze its resilience and overhead within the framework. The scheme exhibits a threshold property whereby compromising fewer nodes than the threshold leaves inter‑node communications essentially uncompromised, thereby raising the cost of small‑scale attacks and demanding a large fraction of nodes to be breached for significant gain.

Abstract

To achieve security in wireless sensor networks, it is important to be able to encrypt and authenticate messages sent between sensor nodes. Before doing so, keys for performing encryption and authentication must be agreed upon by the communicating parties. Due to resource constraints, however, achieving key agreement in wireless sensor networks is nontrivial. Many key agreement schemes used in general networks, such as Diffie-Hellman and other public-key based schemes, are not suitable for wireless sensor networks due to the limited computational abilities of the sensor nodes. Predistribution of secret keys for all pairs of nodes is not viable due to the large amount of memory this requires when the network size is large.In this paper, we provide a framework in which to study the security of key predistribution schemes, propose a new key predistribution scheme which substantially improves the resilience of the network compared to previous schemes, and give an in-depth analysis of our scheme in terms of network resilience and associated overhead. Our scheme exhibits a nice threshold property: when the number of compromised nodes is less than the threshold, the probability that communications between any additional nodes are compromised is close to zero. This desirable property lowers the initial payoff of smaller-scale network breaches to an adversary, and makes it necessary for the adversary to attack a large fraction of the network before it can achieve any significant gain.