A Lightweight Key Freshness Scheme for Wireless Sensor Networks

Secret key establishment and freshness are challenging task in resource constrained wireless sensor networks (WSNs). A large number of messages are exchanged for key establishment at startup and every time a node join or leave the group to refresh keys. These operations incur huge computation and communication cost that reduces the network life time. To minimize energy consumption and improve network lifetime, this paper presents a lightweight XOR based Key Freshness Scheme (XKFS), which allows refreshing the key without inter node message transmission. A single message containing a magic word is transmitted by the group head to its member nodes and keys are refreshed using XOR and left shift operations. XKFS only requires a light weight message from a more powerful head node and thus eliminates the inter node communication cost. The performance of the XKFS is validated through simulations. Simulation results demonstrate the performance supremacy of XKFS over contemporary schemes in terms of minimizing key freshness operations and energy consumption.