Verifiable Attribute-Based Searchable Encryption over RLWE for Secure Data Sharing

Attribute-based searchable encryption (ABSE) is a fundamental primitive for secure data sharing and outsourcing. However, to enhance post-quantum security, existing lattice-based ABSE schemes suffer from two critical limitations: vulnerability to (insider) keyword guessing attacks (KGA) and the inability to verify the correctness of outsourced search results. In this paper, we propose a verifiable attribute-based searchable encryption scheme based on the ring learning with errors (RLWE) assumption. Our construction preserves fine-grained access control while achieving resistance against (insider) KGA and enabling the verifiability of search results. We formalize comprehensive security models capturing multi-keyword ciphertext and token scenarios, and prove indistinguishability under the RLWE assumption. Theoretical and experimental evaluations demonstrate that, for complex access policies, our scheme achieves speedups of approximately 6× and 660× in encryption, and 16× and 940× in token generation over LWE schemes. This efficiency makes it highly suitable for practical post-quantum cloud environments.