Large Universe Revocable Fine-Grained Encryption with Public Auditing

Attribute-based encryption (ABE) allows for scalable and fine-grained data sharing in a cloud computing environment. However, most of existing ABE schemes with user revocation are not satisfactory on the efficiency side. In addition, since the data are stored on remote servers in the cloud storage environment, data owners do not know whether data is integrated in a timely manner. In this paper, we propose a novel large universe revocable fine-grained encryption with public audit- ing (LRA-FE) scheme based on prime-order bilinear groups. In this construction, we utilize extended proxy-assisted approach and appending redundancy approach, which weakens the trust of the cloud server. Furthermore, the proposed system in- troduces an auditor to inspect the integrity of data stored in the cloud. The size of attribute space can be exponentially large because our construction supports large u- niverse. After comprehensive comparisons with the state-of-the-art works, the LRA- FE scheme features lightweight computation at the user side such that users can use resource-constrained devices to access cloud data.