Efficient and Expressive Keyword Search Over Encrypted Data in Cloud

Abstract

In this paper, we propose an expressive public-key searchable encryption scheme in prime-order groups that allows keyword search policies (i.e. predicates, access structures) to be expressed in conjunctive, disjunctive or any monotonic Boolean formulas and achieves significant performance improvements over existing schemes. Efficient and Expressive Keyword Search Over Encrypted Data in Cloud We formally define its security and prove in the standard model that it is selectively secure. We also use a rapid prototyping tool called Charm, to implement the proposed scheme and conduct several experiments to evaluate its performance. Results show that our scheme is much more efficient than those built over the composite-order groups.

Introduction

Efficient and Expressive Keyword Search Over Encrypted Data in Cloud Consider a cloud-based healthcare information system that hosts outsourced personal health records (PHRs) from different healthcare providers. To comply with privacy regulations like HIPAA, the PHRs are encrypted. In order to facilitate data use and sharing, it is highly desirable to have a searchable encryption (SE) scheme that allows the cloud service provider to search for encrypted PHRs on behalf of authorized users (such as medical researchers or doctors) without learning the underlying plaintext information.