Forward/Backward and Content Private DSSE for Spatial Keyword Queries

Abstract

Spatial keyword queries are attractive techniques that have been widely deployed in real-life applications in recent years, such as social networks and location-based services. However, existing solutions neither support dynamic update nor satisfy the privacy requirements in real applications. In this article, we investigate the problem of Dynamic Searchable Symmetric Encryption (DSSE) for spatial keyword queries. First, we formulate the definition of DSSE for spatial keyword queries (namely, <inline-formula><tex-math notation="LaTeX">$\mathsf {DSSE}_{\mathsf {SKQ}}$</tex-math></inline-formula> ) and extend the DSSE leakage functions to capture the leakages in <inline-formula><tex-math notation="LaTeX">$\mathsf {DSSE}_{\mathsf {SKQ}}$</tex-math></inline-formula> . Then, we present a practical <inline-formula><tex-math notation="LaTeX">$\mathsf {DSSE}_{\mathsf {SKQ}}$</tex-math></inline-formula> construction based on geometric prefix encoding inverted-index and encrypted bitmap. Rigorous security analysis proves that our construction can achieve not only forward/backward privacy but content privacy as well, which can resist the most existing leakage-abuse attacks. Evaluation results using real-world datasets demonstrate the efficiency and feasibility of our construction. Comparative analysis reveals that our construction outperforms state-of-the-art schemes in terms of privacy and performance, e.g., our construction is <inline-formula><tex-math notation="LaTeX">$175\times$</tex-math></inline-formula> faster than existing schemes with only 51% server storage cost.