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.

The integration of Internet of Things (IoT) with cloud–edge computing in cyber–physical systems has revolutionized the way healthcare enterprises manage electronic health records (EHRs). With more healthcare enterprises outsourcing encrypted EHRs to the cloud, searchable encryption (SE) is utilized to retrieve encrypted data, especially attribute-based SE (ABSE) can achieve fine-grained access control. However, ABSE usually requires a lot of computation, which imposes a serious burden on resource-limited devices. Moreover, ensuring fairness in data access is crucial in the healthcare domain, where both data users and owners may have conflicting interests. In order to overcome these problems, this article proposes an SE scheme with fine-grained access control for cloud-based EHRs sharing assisted by blockchain. It transfers computing tasks to edge servers and enables users to control who has access to their EHRs. The adoption of blockchain and smart contracts guarantees data integrity and transaction fairness. Moreover, a consensus algorithm is designed for the higher efficiency of the proposed scheme. Finally, security analysis proves that the proposed scheme resists adaptive chosen keyword attacks (CKAs). Performance analysis further confirms that it has more functionalities and is efficient for smart healthcare.

The implementation of immunity passport has been hampered by the controversies over vaccines in various countries, the privacy of vaccinators, and the forgery of passports. While some existing schemes have been devoted to accelerating this effort, the problems above are not well solved in existing schemes. In this paper, we present an immunity passport scheme based on the dual‐blockchain architecture, which frees people from the cumbersome epidemic prevention process while traveling abroad. Specially, the dual‐blockchain architecture is established to fit with the scenarios of immunity passport. Searchable encryption and anonymous authentication are utilized to ensure users’ privacy. In addition, the performance and security evaluations show that our scheme achieves the proposed security goals and surpasses other authentication schemes in communicational and computational overheads.