Verifiable attribute-based multi-keyword ranked search scheme in blockchain

Abstract In recent years, cloud storage has gradually become a promising tool for providing data sharing and data storage services with privacy protection. However, to enable users to search over encrypted data and to enable data owners to perform fine-grained search authorization on their encrypted files is still a great challenge. Although attribute-based keyword search (ABKS) is a well-received solution to the challenge, the direct adoption of the traditional ABKS schemes in cloud storage suffers two issues. The first problem is the lack of integrity verification of search results. That is, the users cannot verify whether the server has actually performed a search without compromise. The second issue is that the retrieval modes of most ABKS schemes are not flexible enough. Aiming at the above two issues, a verifiable ABKS scheme is proposed herein. Besides, we proposed security definitions for two types of adversaries and proved that the proposed scheme is verifiable and able of resisting outside keyword guessing attack and chosen keyword attack. Finally, we carried out all-round simulations with actual data set, showing that the proposed scheme has advantage in efficiency over other similar schemes.