Secure Feedback Service in Wireless Sensor Networks

In many sensor network applications, it is critical for the base station to know the delivery (or execution) status of its broadcast messages (or commands). One straightforward way to do so is to let every sensor node send an authenticated acknowledgement (ACK) to the BS directly. However this naive solution is highly communication inefficient and may result in severe ACK implosion near the BS. In this paper, we propose a communication efficient scheme to provide secure feedback service in sensor networks. In our basic scheme, we use ACK aggregation to reduce the ACK traffic. Meanwhile we store audit information for each aggregation operation so that the BS can use the audit information to locate errors in the network. We further improve the basic scheme by constructing a balanced aggregation tree to reduce localization delay and using Bloom filters to reduce storage requirement in each sensor for storing audit information. We analyze the performance of the proposed scheme and show it achieves good bandwidth gain over the naive approach.