Paper 2020/553

Revocable Attribute-based Encryption Scheme with Arithmetic Span Program for Cloud-Assisted IoT

Hu Xiong, Jinhao Chen, Minghao Yang, and Xin Huang

Abstract

Efficient user revocation and description of the access policy are essential to enhance the practicality of attribute-based encryption (ABE) in real-life scenarios, such as cloud-assisted IoT. Nevertheless, existing ABE works fail to balance the two vital indicators. Motivated by this, in this paper, we present a revocable ciphertext-policy attribute-based encryption with arithmetic span programs (R-CPABE-ASP) for cloud-assisted IoT. For the first time, the presented R-CPABE-ASP achieves efficient user revocation and expressive description of access policy simultaneously. In R-CPABE-ASP, each attribute involved in access policy is merely used once to check whether a user owns access to shared data. Hence, the R-CPABE-ASP work enables efficient data encryption compared with existing revocable ABE works by reducing unnecessary cost for defining access policy. Meanwhile, the forward security of sensitive data is ensured by periodical update of encrypted data such that the capability of revocable storage is also assured in R-CPABE-ASP. As shown in the outsourced version of R-CPABE-ASP, The costly part for users to decrypt the data is outsourced to powerful cloud servers. There- fore, users in our R-CPABE-ASP can access their data in a more efficient way by merely one exponential operation. Finally, we carry out detailed theoretical analysis and experimental simulations to evaluate the performance of our work. The results fairly show that our proposed work is efficient and feasible in cloud-assisted IoT.