Authentication in flat Wireless Sensor Networks with mobile nodes

Secure communication in Wireless Sensor Networks (WSNs) requires the verification of the identities of network nodes. This is to prevent a malicious intruder from injecting false data into the network. We propose an entity authentication protocol for WSNs, and show how its execution can be integrated as part of routing protocols. The integration between routing and authentication leads to two benefits. First, authentication is guided by routing; only nodes on a data path to the base station authenticate each other. Unnecessary protocol executions are therefore eliminated. Second, malicious nodes are not able to use the routing protocol to insert themselves into data paths. Our protocol assumes a flat WSN, i.e., no clustering or cluster heads. We also deal with node mobility issues by proposing a re-authentication protocol that an initially authenticated node uses when its position changes. Finally, we show how to implement the protocol using the TinyOS operating system.