The architecture of two-tiered sensor networks, where storage nodes serve as an
intermediate tier between sensors and a sink for storing data and processing queries, has
been widely adopted because of the benefits of power and storage saving for sensors as
well as the efficiency of query processing. However, the importance of storage nodes also
makes them attractive to attackers. In this paper, we propose SafeQ, a protocol that prevents
attackers from gaining information from both sensor collected data and sink issued queries …