Secure fine-grained spatio-temporal Top-k queries in TMWSNs

TMWSNs (Tiered Mobile Wireless Sensor Networks), which can be seen as a novel paradigm of mobile edge computing, attracts more and more attentions because of their high scalability, good robustness, and perfect deployment flexibility. However, TMWSNs are facing security threat because their key nodes, namely the storage nodes, are much more prone to be captured by the adversaries and become malicious. With the storage nodes captured, all the data stored on them are disclosed to the adversaries, and the data processing at the storage nodes is no longer secure either. In this paper, we focus on the privacy-and-integrity preservation for fine-grained spatio-temporal Top-k queries in TMWSNs, and propose two different schemes which are named as SSSTQ1 (Scheme 1 for Securing Spatio-temporal Top-k Queries) and SSSTQ2 (Scheme 2 for Securing Spatio-temporal Top-k Queries) respectively. SSSTQ1 is much fit for scenarios where the mobile sensor nodes in TMWSNs only move within their own cells, while SSSTQ2 can be exploited in the case that the mobile sensor nodes move freely in the whole network deployment field with a little sacrifice of efficiency and security. We illustrate their performances on energy efficiency and security through both extensive simulations and theory analysis.