Blockchain-Powered Dynamic Context- Verified Smart Contract-Enabled Block Attribute-Based Access Control (BABAC) for Privacy-Aware Healthcare Data Sharing

The rapid adoption of Electronic Health Records (EHRs) and the expansion of distributed healthcareenvironments have intensified the demand for access control mechanisms that are secure, privacy-preserving, andadaptable to diverse clinical scenarios. Traditional models such as Role-Based Access Control (RBAC) struggle tooperate effectively in dynamic healthcare settings where contextual factors- such as emergency conditions, timeconstraints, and geographic location- directly influence authorization decisions. Attribute-Based Access Control(ABAC), grounded in subject, resource, action, and environment (SRAE) attributes, offers a more flexiblealternative; however, its practical realization in decentralized architectures and context-driven healthcareapplications remains limited. Recent blockchain-based access control solutions introduce decentralized policyenforcement and immutable auditing. Nevertheless, many existing frameworks do not adequately support real-timecontextual changes or fully protect the privacy of the access decision process, particularly in permissioned blockchain environments designed for fine-grained control [1].To address these limitations, this study proposes a blockchain-powered, context-sensitive, smart contract-enabled ABAC framework for privacy-aware healthcare data sharing. The proposed system integrates dynamically verified context attributes into the access decision algorithm andenforces context-aware ABAC policies through smart contracts deployed on a permissioned blockchain. Contextualinformation—such as emergency status, temporal constraints, and spatial location—is validated through trustedoracles before policy execution, enabling adaptive and responsive authorization in time-critical clinicalsituations.Unlike earlier approaches that rely on static policies or require disclosure of attribute values [2], theproposed framework demonstrates improved adaptability and enhanced privacy guarantees when compared withbaseline ABAC and conventional access control mechanisms. Performance evaluation indicates that these benefits areachieved with only moderate overhead in decision latency and blockchain transaction costs. Overall, the results highlight that context-aware ABAC implemented via blockchain smart contracts represents a scalable and privacy-preserving authorization model suitable for modern healthcare data-sharing ecosystems.