Key distribution is an important problem in wireless sensor networks where sensor nodes
are randomly scattered in adversarial environments.
Due to the random deployment of sensors, a list of keys must be pre-distributed to each sensor node before deployment. To establish a secure communication, two nodes must share common key from their key-rings. Otherwise, they can find a key- path in which ensures that either two neighboring nodes have a key in common from source to destination. Com-
binatorial designs are powerful mathematical tools with comprehensive and simple structures. Recently, many researchers have used combinatorial designs as key pre-distribution scheme in wireless sensor networks. In this paper we consider a hybrid key pre-distribution scheme based on Balanced Incomplete Block Design. We consider a new approach for choosing key-rings in the hybrid symmetric design to improve the connectivity and resilience. Performance and security properties of the proposed scheme are studied both analytically and computationally. The
obtained results show that our scheme provides better resilience than symmetric design.