Design and Implementation of Hybrid Broadcast Authentication Protocols in Wireless Sensor Networks
A Wireless Sensor Network (WSN) is a wireless network consisting of spatially distributed resource constrained sensor nodes which can cooperatively monitor physical or environmental conditions. The wide applications of WSN and the challenges in them have attracted many researchers to develop protocols and algorithms. Broadcasts are important network functions in WSN, they are used in many applications and protocols such as networks query, software updates, time synchronization, multihop routing, and so on. Broadcast authentication is an essential service in WSN that ensure the broadcast packets from a valid source were not altered in transmit. Many broadcast authentication protocols have been proposed for WSN. These protocols can be classified into two categories. One is based on digital signature technologies, such as TinyECC, TinyPK. The other is based on improved message authentication codes, such as ?TESLA, PBA. Some works were proposed to design hybrid broadcast authentication protocols. These works commonly use digital signature in base station or cluster head, and use improved MAC in sensor nodes. The idea about more computation efficiency of protocols based on improved MAC comes from the analysis of algorithm complexity, simulation and testbed where broadcast authentication is only applied to packets from base station. Consequently, the hybrid broadcast authentication protocols based on this conclusion are not practical. For example, ?TESLA needs loose time synchronization between broadcast sender and receiver.