SPIKE: Scalable Peer Intermediaries for Key Establishment in Sensor Networks

In a sensor network, common-key cryptography is used to establish secure communications between nodes. Since it is required to share the common key between nodes in advance to the communication, a key establishment scheme should be considered. Chan and Perring proposed a novel key establishment scheme PIKE (Peer Intermediaries for Key Establishment in Sensor Networks) in which each common key used in each communication between nodes is derived from a pre-shared key, and all common keys are different from each other. In addition, each node is required to have small number of pre-shared keys. However, the number of pre-shared key grows as the number of nodes in the network grows, and more importantly, PIKE has a problem that when the network is established, it is hard to add new nodes into the network, since storing new pre-shared keys in existing nodes is required. This paper proposes a new key establishment scheme SPIKE (Scalable Peer Intermediaries for Key Establishment in Sensor Networks), in which all nodes in the network are required to have a constant number of pre-shared keys. The proposed scheme allows the network to add new nodes after the network has been established.