QS-CPABE: Quantum-Safe CP-ABE with policy hiding and verifiable policy update for cloud storage

Ciphertext-Policy Attribute-Based Encryption (CP-ABE) ensures data privacy and fine-grained access control in a cloud environment through its one-to-many encryption feature. However, most of the existing CP-ABE schemes cannot resist quantum attacks as they are constructed from bilinear pairing assumptions. Recently, several lattice-based CP-ABE schemes have been proposed to defend against quantum attacks, but these schemes do not provide mechanisms to hide the policy attributes along with a verifiable policy updating mechanism which is crucial for dynamic access control management in cloud environments. To address these issues, this paper proposes a Quantum-Safe CP-ABE scheme with policy hiding and verifiable policy updates for cloud storage. The security of QS-CPABE is proven against the Chosen Plaintext Attack (CPA) under the Module Learning with Errors (M-LWE) assumptions. The theoretical and experimental analyses demonstrate that QS-CPABE is practical and efficient.