An efficient encrypted search with owner-level and attribute-level access controls

Abstract

With more and more attention to the security of cloud storage, people are increasingly inclined to remotely store their encrypted data. In what follows, many searchable encryption (SE) schemes have been proposed. Unfortunately, the existing SE schemes under multi-user and multi-owner model are usually inefficient in owner-level and attribute-level access controls. Therefore, this paper aims to further improve the efficiency of the encrypted search with two-level access control. In our design, the owner-level permission is inspired by BLS signature and the attribute-level permission is based on CP-ABE, both of which are driven by simplifying the related keys as much as possible, allowing users to efficiently search data from multiple owners by using a single trapdoor. In addition, the proposed scheme can also efficiently support permission revocation, thanks to our simplified key for a user which can be independently updated without affecting other users. For the sake of security, we perform the random masking technique on encrypted index and searching trapdoor for hiding the keyword embedded in them, while keeping their matching relationship for keyword search. The proposed scheme is strictly proven to have the security properties of keyword secrecy, keyword irreplaceability, two-level controlled search and forward secrecy. Finally, we give plenty of theoretical analysis and experimental results to validate the superiority of the proposed scheme.