Privacy-preserving secure data sharing in edge-cloud collaborative environments

In cloud computing environments, data sharing serves as a foundational enabler of collaborative operations across heterogeneous terminals. However, such sharing introduces critical challenges–including privacy leakage, inadequate data security, inflexible access control policies, and substantial computational latency. To address these limitations, this paper proposes a privacy-preserving, secure data-sharing framework tailored for edge-cloud collaborative architectures. Relative to conventional approaches, the proposed framework delivers three principal advancements: (1) User Privacy Protection: We design a secure query-matching algorithm that protects plaintext query keywords during data access. The Cloud Server (CS) performs matching over encrypted trapdoors without directly learning the queried keywords. (2) Computational Efficiency Improvement: Edge Servers (ESs) perform outsourced ciphertext transformation using user-specific transformation keys. The terminal only performs a lightweight local operation to recover the resource. This approach minimizes the computational overhead on the terminal side while safeguarding user privacy, and effectively reduces the overhead associated with user joining and revocation within the same group. (3) Fine-Grained, Policy-Driven Access Control: A cryptographically enforced, attribute- and keyword-aware access control mechanism is implemented, supporting precise, context-sensitive authorization decisions via encrypted keyword search and semantic matching–thereby enhancing both the security posture and operational flexibility of data access control.