A Hybrid NIZKP and Schnorr’s Protocol-Based Two-Factor Authentication for Secure and Scalable Healthcare Systems

Abstract

Healthcare information systems increasingly rely on networked access to electronic health records and clinical services, making authentication latency and usability as critical as cryptographic strength. This paper presents a lightweight hybrid authentication framework that combines Schnorr identification with a Fiat-Shamir-derived non-interactive zero-knowledge proof (NIZKP), integrates a conventional second factor (OTP and/or biometric), and enforces role-based access control (RBAC). The design eliminates transmission of reusable password secrets during routine logins, keeps proof material constant-size, and targets fast verification suitable for high-throughput hospital gateways. We implement the pipeline and evaluate it under three simulated clinical traffic patterns aligned with eICU-inspired workload modeling: low traffic (50 users), high traffic (500 users), and burst peak load (100 users). Across scenarios, the end-to-end authentication time remains stable between 0.0107 s and 0.0109 s and stays below a 0.02 s benchmark. Reliability remains high, with success rates of 100.0%, 99.8%, and 99.0%; observed failures stem from injected OTP-expiry or biometric-mismatch events rather than cryptographic verification errors. These results suggest that Schnorr-style NIZKP authentication can provide privacy-preserving, scalable access control for healthcare environments when combined with practical 2FA and RBAC enforcement.