Policy-Bound, Verifier-Pluggable Smart Contract Framework for Auditable Healthcare Analytics

Healthcare analytics involving sensitive patient data demand robust statistical safeguards alongside verifiable compliance mechanisms that allow regulators to independently reconstruct query operations, applied policies, and reported outcomes without accessing raw medical information.We present a governance-first, upgradeable on-chain framework that anchors complete request lifecycles to public blockchain using keccak256 cryptographic commitments. This approach delineates a process wherein researchers submit structured queries, a controller captures active policy states, and hospitals provide result digests. A comprehensive and immutable event trail for this entire process is maintained on the Ethereum Sepolia blockchain. External auditors can then reconstruct complete timelines and verify consistent binding between requests, policies, and outcomes. The proposed modular verifier interface, currently implemented via configurableMockVerifier, maintains stable Application Binary Interface compatibility for future production verifier integration while validating end-to-end governance. We demonstrate the framework’s practicality through a detailed diabetes prevalence analytics case study. We provide detailed gas consumption profiles, request latency measurements, and observable failure modes that demonstrate how governance rules translate into enforceable reversions. The architecture maintains minimal on-chain state with Layer-2 readiness, offering immediate regulatory accountability while preserving straightforward upgrade paths to advanced cryptographic components like zk verifiers (Groth16), verifiable differential privacy through VRF-seeded randomness, content-addressed artifact storage, and versioned policy management. This approach effectively separates initial deployment feasibility from computationally intensive cryptography while delivering immediately actionable, externally verifiable evidence of policy compliance.