Secure and Efficient Top-k Query Processing in Two-Tier Sensor Network

In two-tier sensor networks, resource-rich storage nodes at the upper tier collect sensing data from resource-poor sensor nodes at the low tier and answer queries from the network owner. Sensor nodes perform sensing task and submit sensing data in one time-slot to the nearest storage node while storage nodes answer and process the query from the network owner. However, in hostile environments, the storage nodes performing query processing and storing sensing data confront serious security concerns, thus storage nodes may be compromised and then instructed to return fake query results. Therefore, it is important to verify the correctness of query results. A secure and efficient query processing scheme is proposed to verify the authenticity and completeness of top-k query answers on sensing data in one time-slot, which is the first of secure top-k query processing performed on the time-slot sensing data set. Through hypothesis testing method combined with computing commitment, we effectively increase the detection rate and reduce the additional communication cost for enabling verifiable top-k queries, which force compromised storage nodes to return both authentic and complete top-k query results to the network owner. Theoretical analysis and simulation results successfully validate the efficacy and efficiency of the proposed schemes.