uFETCH: A Unified Searchable Encryption Scheme and Its Saas-Native to Make DBMS Privacy-Preserving

As encrypted-search techniques such as Searchable Encryption (SE) were devised for homogeneous data type, i.e. textual or numerical, it is a nature presumption that multiple techniques have to be intertwined to make database management system (DBMS) privacy-preserving. In effect, such a presumption has led to popular designs such as CryptDB, putting efforts on heterogeneous integration. In this paper, an easier option is made available when a unified SE scheme named uFETCH is proposed to accommodate both. Namely, uFETCH is able to build unified SE indexes for both the types while enabling encrypted search even if the SE indexes built for texts and numbers are mingled. To demonstrate how uFETCH can bring up simpler designs, a security agent is exemplified to work with off-the-shelf DBMS while making it privacy-preserving. Since uFETCH transforms the problem of encrypted search into a simple problem of subsequence matching for SaaS-native, it requires only sub-linear search time w.r.t. the volume of indexed items and is secure in the widely-adopted 3-tier cloud structure to help cloud service providers ease regulation compliance with out-sourced repository.