Decentralized biometric verification of patients: a Blockchain-IPFS-Oracle hybrid architecture with evaluation performance and GDPR compliance

Abstract

Biometrics plays a key role in digital identity management, particularly in healthcare environments where secure authentication, data integrity, and regulatory compliance are critical. However, conventional centralized biometric systems suffer from major limitations, including irreversible data compromise, insider threats, and poor alignment with data protection regulations such as the General Data Protection Regulation (GDPR). This paper proposes a decentralized biometric patient identity verification architecture based on a hybrid Blockchain-IPFS-Oracle model. The proposed system separates on-chain identity management from off-chain encrypted biometric storage and verification, using modular smart contracts for traceability and governance, IPFS for distributed encrypted storage, and a trusted oracle for confidential biometric comparison. This design enhances data sovereignty, mitigates single points of failure, and improves resistance to internal manipulation. An experimental proof of concept was implemented and evaluated in terms of enrollment and verification latency, blockchain execution costs, and duplicate detection accuracy. The results demonstrate the technical feasibility of the proposed architecture in healthcare-oriented scenarios, while offering improved GDPR compliance and scalability compared to traditional centralized approaches.