Practical Multi-Authority Ciphertext Policy Attribute-Based Encryption from R-LWE

Attribute-Based Encryption (ABE) has been caught a wide range of attention owing to its advantage of achieving both fine-grained access control and protection for data. In recent years, the constructions of ABE have developed to lattice-based schemes, while most of them exist bottlenecks in efficiency and security as a result of constructing on the Learning With Errors (LWE) assumption and relying on a single central authority. In this paper, we propose a decentralized multi-authority Ciphertext-Policy Attribute-Based Encryption (CP-ABE) scheme from the Ring Learning With Errors (R-LWE) assumption, which supports flexible access policies and is built on a new trapdoor with efficient algorithms. Moreover, in our system, management and distribution for the private keys are accomplished by multiple authorities utilizing the technique of Shamir threshold secret sharing, which makes it more efficient and applicable to the distributed storing environments. We then prove that the scheme is selective secure under chosen plaintext attacks. The experimental results manifest that the proposed scheme can be carried out in a comparatively short amount of time, which confirms its practicality.