Authentication in Reprogramming of Sensor Networks for Mote Class Adversaries

Reprogramming is an essential service for wireless sensor networks. Authenticating reprogramming process is important as sensors need to verify that the code image is truly from a trusted source. There are two ways to achieve authentication: public key based and symmetric key based. Although previous work has shown that public key authentication is feasible on sensor nodes if used sparingly, it is still quite expensive compared to symmetric key based approach. In this paper, we propose a symmetric key based protocol for authenticating reprogramming process. Our protocol is based on the secret instantiation algorithm from, which requires only O(log n) keys to be maintained at each sensor. We integrate this algorithm with the existing reprogramming protocol. Through simulation, we show that it is able to authenticate reprogramming process at very low communication cost, and has very short delay.