A lattice-based CP-ABE scheme with immediate attribute revocation

Ciphertext-policy attribute-based encryption (CP-ABE) is suitable for providing secure data-sharing services in the cloud storage scenario. However, attribute revocation in CP-ABE is a sticky issue. The research achievement on quantum computing makes the traditional CP-ABE no longer secure. Fortunately, lattice-based CP-ABE can resist quantum attacks. This paper proposes a lattice-based CP-ABE scheme with a tree access structure that supports the immediate revocation of attributes. This scheme is resistant to quantum and collusion attacks. When attribute revocation occurs, the semi-trusted third party implements the immediate attribute revocation to handle dynamic user permission changes immediately. The proposed re-encryption algorithm can effectively reduce the computational complexity of ciphertext re-encryption during attribute revocation, and the lazy ciphertext update method reduces the scope and size of the ciphertext update. Finally, it is shown that, under the standard model, the scheme is proven secure against chosen-plaintext attacks (CPA), and its security can be attributed to the learning with errors (LWE) difficulty problem.