Practical revocable and multi-authority CP-ABE scheme from RLWE for Cloud Computing

Cloud computing provides enterprises and individuals with unlimited computing resources and expandable storage space. However, data leakage occurs frequently due to the lack of protection measures in the cloud storage environment. Consequently, how to protect data security in the cloud has become a critical issue. Attribute-based encryption (ABE) is an emerging encryption technique, which protects sensitive information and provides access control for data stored in the cloud. However, most of existing ABE schemes cannot resist quantum attacks and lack the capability of implementing flexible revocation on user or attribute when the attributes of a user change, which hinders the practical application of ABE. In this research, we present a Revocable and Multi-authority ciphertext-policy attribute-based encryption (RM-CP-ABE) from the ring learning with errors (RLWE) assumption, which supports multi-authority and multi-valued attributes. The scheme allows multiple authorities to involve in key distribution, and achieves the attribute revocation when the user’s access rights change. Also, the scheme enjoys reasonable computational cost and storage overhead, and is proven selectively secure under the RLWE assumption. The simulation results indicate that the performance of the proposed scheme is acceptable for practical applications.