Secure Fine-Grained Multi-Keyword Ciphertext Search Supporting Cloud-Edge-End Collaboration in IoT

The massive terminals access the Internet of things (IoT) through edge nodes, bringing forth new security and privacy challenges in ciphertext search and data sharing. Meanwhile, existing ciphertext search schemes often overlook lightweight computing paradigms and pay little attention to the search requirements of multiple data owners (DOs)/data users (DUs). To address these issues, we propose a secure fine-grained multi-keyword ciphertext search scheme with cloud-edge-end collaboration computing (SFMS-CC). This SFMS-CC scheme focuses on the efficiency of end users and employs a cloud-edge-end collaborative computing paradigm, effectively offloading the incremental overhead from terminals and achieving low-cost constant overhead for the first time on the DO/DU side. Furthermore, based on public-key cryptography, a ciphertext search framework supporting multi-keyword is presented systematically. Each user is assigned an exclusive search Tok to enhance the user experience. Additionally, by integrating attribute-based encryption (ABE), a multi-DOs/multi-DUs model is constructed, seamlessly embedding entity private keys and public keys into encryption, search, decryption, and other steps, ensuring high privacy and security of this scheme. Security analysis demonstrates that the SFMS-CC scheme withstands choose plaintext attack (CPA), providing privacy-preserving for outsourced data and user information. Simulation results indicate that the SFMS-CC scheme is efficient and feasible in practice.