An Exact Top-k Query Algorithm with Privacy Protection in Wireless Sensor Networks

Aimed at the Top-k query problems in the wireless sensor networks (WSN) where enquirers try to seek the k highest or shortest reported values of the source nodes, using privacy protection technology, we present an exact Top-k query algorithm based on filter and data distribution table (shorted for ETQFD). The algorithm does the query exactly and meanwhile uses conic section privacy function to prevent the disclosure of the real data and then to promise the security of nodes in network. In this proposal, each node in WSN uses data distribution table to reflect the distribution of its own data and keeps exact filter to just return data which is possibly to be the result of the query, so as to reduce the energy cost of network and prolong network lifetime. In addition, data of node is packaged with a privacy protection function based on conic section. The algorithm's performance is examined with respect to a number of parameters using synthetic datasets. Performance analysis and simulation results illustrate that, compared to existing algorithms, ETQFD is energy-efficient and the network lifetime in our algorithm is longer. At the same time, privacy of data in this algorithm is also guaranteed.