Key predistribution schemes for wireless sensor networks based on combinations of orthogonal arrays

In general, combinatorial key predistribution schemes (KPSs) have higher local connectivity but lower resilience against a node capture attack than random KPSs for a given key storage. We seek to find an approach to improving the weakness of combinatorial KPSs while maintaining the strength as much as possible. In this paper, by combining a class of saturated symmetric orthogonal arrays (OAs), a family of KPSs are proposed and the explicit formulas for local connectivity and resilience of the resulting KPSs are also derived. KPSs are typically designed to provide a trade-off between the key storage, the local connectivity and the resilience. It is found that in the resulting schemes, any two nodes can communicate directly with each other and for a given key storage, the resilience against node capture increases as the number of OAs increases so that the resilience can be enhanced without degrading the other two metrics.