The adoption of blockchain technology in healthcare has significantly enhanced data integrity, transparency, and user privacy. However, high storage overhead and resource-intensive operations remain major challenges to its widespread deployment, particularly in large-scale or resource-constrained healthcare environments. To address these challenges, we propose STORChain, a storage-optimized blockchain framework designed for data services in healthcare. The framework introduces the Clustered Merkle Patricia Tree (C-MPT), a novel logical structure that aggregates similar transaction types to maximize storage efficiency while ensuring Proof of Inclusion (PoI). A Selective Transaction Pruning Strategy (STPS) is employed to prioritize and prune essential historical data, improving data access efficiency. Additionally, an incentive-based Delegated Proof-of-Stake (DPoS) consensus algorithm is utilized, integrating a probabilistic election mechanism to promote fairness and node inclusivity. Comprehensive theoretical analysis and practical experiment results indicate that STORChain significantly reduces storage overhead, optimizes data access, and outperforms existing schemes.

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 article 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.