Research in Wireless Sensor Networks (WSNs) has made a significant progress recently, especially the area of key management, which plays a central role for protecting group communication in sensor networks. In sensor networks, the data are crucial and have to keep secrecy in data communication. To achieve data confidentiality, adversary should not have access to the group communication. Therefore due to the limited memory resources and energy constraints of sensor nodes, reducing the communication and storage overhead, and improving the resilience against the node capture attack become a must.

In this paper we propose An Efficient Group Key Management using Symmetric Key and Threshold Cryptography for Cluster based Wireless Sensor Networks (EGKMST). The proposed scheme considers a hierarchical cluster structure of sensor network and adopts the pair-wise key management and group key management based on threshold key cryptography to generate and to distribute the keys efficiently within a cluster and updates periodically keys. By this way EGKMST provides continuous transmission security and avoids dangerous attacks from malicious nodes and mitigate the node compromise attack in WSNs communication. The security and performance analysis illustrate that EGKMST scheme achieves the requirement of group communication and provides efficient security with low communication cost, low memory overhead and energy saving compared with some existing key management schemes.