Mutual healing enabled group-key distribution protocol in Wireless Sensor Networks

The unreliable wireless medium for communication within a Wireless Sensor Network (WSN) necessitates equipping the sensor nodes with shared secrets to protect the communication en-route. In order to establish a dynamic session secret amongst a group of sensor nodes in a WSN, group-key broadcast is found to be a workable solution. However, when a node misses one or more group-key broadcast messages, rebroadcasting results in additional energy consumption at node end and increased network traffic as well. Self-healing mechanism is, therefore, used to recover the lost broadcasts using a future session broadcast. A node, that has missed multiple consecutive broadcasts and does not want to wait for a future broadcast, can obtain the session key through mutual-healing with the help of a neighbor node. In this paper, we present a secure and efficient mutual-healing protocol that uses Chinese remainder theorem(CRT) based secret sharing for group key broadcast. During mutual-healing, mutual authentication and key confirmation are provided. The probability of an unauthorized member retrieving a past session key through self-healing or responding to a mutual-healing request as a neighbor node is shown negligible. The experimental results show that the proposed protocol provides significant performance improvement in terms of computation, communication and storage overhead as compared to existing mutual-healing protocols.