Efficient keyword search over encrypted data with fine-grained access control in hybrid cloud

Abstract

As cloud computing becomes prevalent, more and more sensitive information is being centralized into the cloud, which raises a new challenge on how to efficiently share the outsourced data in a fine-grained manner. Although searchable encryption allows for privacy-preserving keyword search over encrypted data in public cloud, it could not work effectively for supporting fine-grained access control over encrypted data simultaneously. In this paper, we consider to tackle the challenge above under a hybrid architecture in which a private cloud is introduced as an access interface between users and public cloud. We firstly propose a basic scheme allowing both exact keyword search and fine-grained access control over encrypted data. Furthermore, an advanced scheme supporting fuzzy keyword search is presented. In both schemes, overhead computation is securely outsourced to private cloud but only left behind the file encryption and decryption at user side. Finally, we demonstrate approaches to realize outsourcing cryptographic access control mechanism and further relieve the computational cost at user side. © 2012 Springer-Verlag.