Efficient and privacy-preserving medical data sharing remains a key challenge in the era of digital healthcare. Existing schemes often suffer from limited access control, substantial computational overhead, and reliance on trusted third parties. This paper proposes a revocable Attribute-Based Searchable Encryption (ABSE) scheme built upon a hierarchical blockchain architecture, which enables a secure keyword search over encrypted data via expressive attribute-based access policies, and a revocation mechanism is integrated to support dynamic user management. We design a lightweight and privacy-preserving computation framework that offloads expensive cryptographic operations to the cloud, thereby reducing the burden on user-side devices. Furthermore, we propose a lightweight consensus protocol, termed lottery consensus, which replaces traditional proof-of-work hash computations with meaningful operations that are tied to the ABSE-based data-sharing process. Extensive theoretical analysis and simulation experiments demonstrate the superior efficiency of the proposed scheme, and formal security proofs demonstrate its robustness against threats.
Gao et al. (Wed,) studied this question.