Deterministic Merging of Blocks in Combinatorial Design based Key Predistribution in Distributed Wireless Sensor Network

Abstract

Sensor nodes have severe constraints in terms of its resources such as processing power, memory, communication range, battery power. Due to wireless nature of communication between nodes in a wireless sensor network, any attacker can intercept the communicating messages between sensor nodes. So the need for securing these messages is obvious. Due to resource constraints of sensor nodes, public key cryptography can’t be employed for securing the communication as public key cryptography demands much computational effort. So, private key cryptography is natural choice for securing the communication in wireless sensor network.
Key predistribution has become obvious choice for distributing keys in sensor nodes for secured communication in a wireless sensor network. A pool of keys is first taken, and then a set of keys from this key pool is installed in every sensor node before their deployment. The keys predistributed to a particular sensor node can be drawn from the key pool probabilistically or deterministically. Combinatorial design which was originated as a branch of statistics and later found its vast application in coding theory and of late in cryptography plays a vital role in deterministic key predistribution.
The connectivity and resiliency offered by some combinatorial design based key predistribution schemes can be sometimes offered by merging of blocks and then assign these merged blocks to sensor nodes. The question is how to choose blocks for merging? There is a prior general work on merging of blocks which has been studied on transversal design based key predistribution scheme. This approach is not deterministic, but heuristic. A deterministic algorithm for merging of blocks has been proposed. The orthogonal array based key predistribution scheme has been studied in detail and the non suitability of merging approach to improve its performance has been shown.
In addition, a key establishment algorithm for transversal design based key predistribution scheme has been proposed.