FSDS: A practical and fully secure document similarity search over encrypted data with lightweight client

Abstract

In this paper, we propose a highly accurate, fully secure document similarity search (FSDS) scheme that makes use of both a novel variant of the secure K-NN algorithm and somewhat homomorphic encryption (SWHE). The scheme provides data, query and search pattern privacy and is amenable to access pattern privacy. We provide formal security analyzes of both the original and the new secure K-NN algorithms and show the latter is IND-CPA secure. We also rely on IND-CPA security of the SWHE scheme to meet the strong privacy claims. The scheme provides a speedup of about two orders of magnitude over the schemes using only SWHE while its overall performance is comparable (and faster for certain cases) to other schemes in the literature with weaker forms of privacy claims. We present implementation results including those from the literature pertaining to response times, storage and bandwidth requirements and show that the proposed scheme facilitates a lightweight client implementation.