Leveled Group Key Management with Efficient Revocations for Wireless Sensor Networks

Wireless sensor networks are often deployed in hostile environments. Protecting the communication against node capture is one of the most important design objectives. Focused on the revocations of resource constrained nodes, an efficient leveled group key management scheme is proposed. This scheme is based on a novel application of an
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-ary logical key tree. Since sensor nodes may leave or join the WSN frequently, a sub-level session key is introduced to protect the sensitive information transmitted in the network. In a leave event, the remaining legal sensors in the key tree are partitioned into disjointed subtrees. The group key can be updated securely by encrypting the new group key with the common keys shared by the sensors in the same subtree. When a sensor requests to join the communication group, it is assigned a sublevel session key which is used to communicate with GCKS and other legal sensors. The current session key is sent to the new sensor only after it gets the trust of GCKS. This scheme is scalable, stateless and simple to employ.