A hybrid design of key pre-distribution scheme for wireless sensor networks

Here a scheme is presented for key pre-distribution in wireless sensor networks. A transversal design is considered to construct a (v, b, r, k) configuration. Then properly chosen blocks are merged to form sensor nodes such that there is no intra-node common key. The choice of blocks in merging is currently made heuristically in a randomized manner. The scheme is called hybrid as a combinatorial design followed by a heuristic is applied. Detailed analysis is presented regarding the number of nodes, number of keys per nodes and the probability that a link gets affected if certain number of nodes are compromised. It is also argued how the scheme compares favourably with the state of the art proposals. Towards the end we also present a result to find out the lower bound on the number of nodes given a certain combinatorial design.