Public-key Searchable Encryption with Index Generation for Shared Database

Abstract

Recently, use of cloud computing has expanded to include tasks such as data sharing among multiple enterprises for open innovations and IoT systems for device management, etc. Public-key searchable encryption is particularly useful for cases requiring protection of shared secret data. However, there is no public-key searchable encryption scheme that simultaneously achieves: (A) efficient search performance, (B) multiuser support and (C) implementation on database management systems, simultaneously. In this paper, we propose a new public-key searchable encryption scheme which (A) provides an index generation mechanism for public-key searchable encryption, and (B) generates different secret keys for multiple users. In our scheme, (A) is achieved by a portion of the deterministic values generated from a keyword, and (B) is achieved by hierarchical inner-product predicate encryption. Our scheme in particular, forms wildcards as the user identity from hierarchical inner-product predicate encryption in order to easily represent hierarchical identities. To achieve (C), we further propose an integration method which implements our scheme into database management systems through a user-defined function so that its search functionality can be easily used via SQL.