A lattice-based multi-authority updatable searchable encryption scheme for serverless architecture with scalable on-demand result processing

Searchable encryption (SE) enables the searchability of encrypted data in cloud environments, thereby safeguarding privacy. Despite this, the actual execution of ciphertext searches within a multi-user data-sharing context necessitates flexible access services for various authorized users. Although the existing solution has achieved ciphertext retrieval with multi-user authorization, it still exhibits shortcomings in areas such as dynamic and manageable permissions and the more granular access control on results. Our scheme, grounded in lattice cryptography, is designed to withstand quantum attacks. It leverages serverless cloud computing and incorporates ciphertext-policy attribute-based encryption (CP-ABE) along with proxy re-encryption (PRE) to construct a multi-user authorization searchable encryption system. This system facilitates keyword searches on encrypted data, supports dynamic multi-user authorization, and ensures scalable, results-on-demand capabilities. Security analysis confirms that our scheme is impervious to collusion attacks, chosen keyword attacks (CKA), and chosen plaintext attacks (CPA). Finally, the performance analysis demonstrates that our scheme is both secure and efficient, outperforming other multi-user searchable encryption schemes in terms of security and efficiency.