Ideal Lattice-Based Efficient Data Sharing Scheme for Cloud Storage

The proliferation of cloud computing has rendered secure data sharing a paramount challenge, particularly in the post-quantum era where quantum computers threaten traditional public-key cryptosystems. While many schemes exist, achieving fine-grained, efficient, and quantum-resistant access control remains a key research area. To this end, this paper proposes a post-quantum secure data sharing scheme based on ideal lattices. We construct a new Ciphertext Policy Attribute-Based Encryption (CP-ABE) scheme for key distribution over ideal lattices, integrated into a hybrid encryption mechanism to protect data privacy efficiently. This approach allows data owners to enforce complex access policies on their encrypted data, ensuring that only authorized users can access it. Rigorous security proofs demonstrate that the proposed scheme is IND-CPA-secure under the Ring-LWE assumption. The efficiency of the scheme is due to its effective utilization of the algebraic structure of the ideal lattice, which accelerates polynomial operations through Number Theoretic Transformations (NTT). Comparative analysis and experimental results show that the scheme has significant advantages in computing efficiency and storage cost, thereby underscoring its practical feasibility for high-throughput cloud environments.