Group Key Distribution Via Local Collaboration In Wireless Sensor Networks

Wireless sensor networks have been recognized as one of the most important technologies in the networking world. Security of sensor networks is one of the major concerns today. To this end, a whole suite of protocols have been designed to provide various security features which includes key management. This thesis covers the issue of group key management in wireless sensor networks. Traditional cryptographic techniques can be used to provide communication privacy and integrity, but do not provide scalable solutions to group key management. A group key management scheme for sensor networks has been discussed that targets at fast response to changes in security conditions. Motivated by the fact that a compromised sensor is most likely to be detected first by its fellow neighboring nodes, the concept of local collaboration during the process of group key distribution is introduced. In the proposed scheme, a sensor node is not able to obtain the secret key solely based on the broadcast message and its pre-deployed secret share. Rather, it has to seek for collaboration from its fellow sensor nodes. Only by jointly exploiting the secret shares disclosed by the broadcast message, its own pre-distributed secret, as well as secrets revealed by other nodes, can a node reconstruct the group key. By empowering the sensor nodes themselves to be able to exclude a compromised node, the scheme promises fast reaction to the ever changing network conditions. Furthermore, a set of enhancements to the basic scheme including self-evolving design for significant reduction in communication and memory overhead are developed.