Wireless Sensor networks are finding revolutionary applications in 24x7 unattended monitoring remotely. Such randomly deployed sensor nodes (SNs) need to send data to a central station, commonly known as base station (BS). SNs have limited energy resources and all possible attempts should be exerted to minimize energy consumption. But, maintaining secured communication poses additional challenges. This paper deals with a novel mechanism in establishing shared symmetric key between any two adjacent SNs by utilizing a 2-D matrix based key pre-distribution scheme between SNs. Versatility of this scheme is illustrated and enhanced resilency is observed in key distribution system. The use of multivariate polynomial is explored to have hierarchical authentication scheme between the BS and SNs be delegating the responsibility to cluster heads.