Multi-Client Searchable Encryption with Granular Access Control for Cloud-Assisted IoT

Cloud-assisted Internet of Things (CIoT) enhances data accessibility and operational efficiency but encounters various security and privacy challenges. Today, CIoT applications generate large amounts of data in a multi-client accessible environment involving periodic addition of data. These systems require efficient searchable encryption to securely share data with authorized users, enable private keyword searches, and support frequent updates to outsourced data, thus maintaining data integrity and user privacy. Existing symmetric searchable encryption (SSE) schemes enable efficient searches for large datasets but are limited in providing multi-user data sharing. In contrast, attribute-based searchable encryption (ABSE) schemes offer fine-grained access control in collaborative scenarios but suffer from high search latency. In this paper, we present a hybrid searchable encryption scheme that enables secure keyword search with sublinear search efficiency and supports periodic dynamic addition of files in multi-client IoT environments. By providing privacy-preserving keyword searches with forward privacy and keyword-level access control, our approach effectively enhances security and performance for cloud-assisted IoT.