A HYBRID BLOCKCHAIN AND ATTRIBUTE-BASED ENCRYPTION FRAME-WORK FOR SECURE AND PRIVACY-PRESERVING DATA MANAGEMENT IN HEALTHCARE 5.0

Abstract

The rapid evolution of Internet of Things (IoT)-based healthcare environments has generated a vast amount of confidential patient data, raising critical concerns about security, privacy, and access control. Traditional centralized storage models are vulnerable to single points of failure and data breaches, and they lack fine-grained policy enforcement. Existing cryptographic approaches struggle to balance privacy, searchability, and scalability. In this context, this research integrates blockchain and attribute-based encryption (ABE) to present a secure, privacy-preserving healthcare data management system that uses Ethereum smart contracts for decentralized authentication and auditability. The system implements ciphertext-policy attribute-based encryption (CP-ABE) for fine-grained, policy-driven access control and an off-chain storage system. A privacy-preserving search mechanism enables authorized healthcare providers to perform keyword-based queries on encrypted data without decrypting it, while smart contracts mediate access and ensure tamper-resistant logging. Security analysis demonstrates that the proposed scheme achieves indistinguishability under chosen-plaintext attack, and performance evaluation shows a throughput of 1.5-2.5 TPS with encryption times ranging from 28.24 ms to 66.88 ms for 5 to 25 attributes. The framework actively addresses the limitations of centralized systems, offering a scalable, secure solution for healthcare data management and sharing.