A Blockchain-Based Privacy-Preserving Framework for Healthcare Data: Survey and System Proposal

Integrating blockchain with healthcare data management promises enhanced privacy, security, and trust in handling
sensitive patient information. This paper reviews privacy-preserving blockchain frameworks—such as Hyperledger Fabric
[1], Ethereum smart contracts [2], MediBchain, and ACHealthChain [5]—and identifies key challenges like limited
scalability, poor interoperability with existing systems, and lack of patient control [3][5][9].To overcome these issues, we
propose a modular architecture combining Hyperledger Fabric [1], off-chain encrypted storage via IPFS [5], and finegrained access using Ciphertext-Policy Attribute-Based Encryption (CP-ABE) [4][6]. Smart contracts enforce access
policies, enabling secure, patient-controlled data sharing without intermediaries. The architecture complies with data
protection laws like HIPAA and GDPR [2][5], and integrates well with current clinical workflows [8][9]. Simulated
evaluation with 10,000 synthetic patient histories demonstrates improved scalability, lower latency, and strong privacy.
Compared to MediBchain [5], our solution supports interoperability and secure federated learning [8], enabling
collaborative, privacy-preserving AI diagnostics. By prioritizing real-world integration, patient autonomy, and privacy, our
framework promotes a decentralized, secure, and future-ready digital health ecosystem.