Insider-resilient database architecture for Nigerian healthcare cybersecurity using SHA-256 and Argon-2id-based two-tier approach

Abstract Cyberthreats threatening data integrity, availability, and patient safety of national healthcare critical infrastructure in resource-limited domains are a growing concern. This research paper proposes a secure two-tier database architecture to achieve higher resilience against remote and insider adversaries through separation of operational storage from integrity verification of data. Its linked crypto hashing using Secure Hash Algorithm-256 (SHA-256) ensures data integrity across tiers; Argon-2id integrated, handles root credentials with role-based access control, and the backup storage is isolated. The process of system design was framed around a formal threat model emphasizing focus on insider tampering, unprivileged or unauthorized escalation of privilege, and the risk of clandestine alteration at the backup tier. The functional tests, adversarial attack simulations, and performance evaluation on simulated healthcare workloads to analyze the system were utilized. The results indicate that the cross-tier integrity verification mechanism detected 97.39% of unauthorized data tampering attempts by an adversary during synchronization cycles and detected integrity violations with a time delay of less than one replication interval (≤ 30 s). Testing of an authentication showed that Argon-2id had an additional login latency (when accessed simultaneously by multiple users) of 38–55 milliseconds, which is acceptable in clinical workflows. Replication performance analysis showed an average additional latency of less than 10% for write operations and that synchronization lags remained under 5 s even during peak traffic. The results indicate that the proposed architecture provides a realistic trade-off between security, performance, and deployability. Our framework has yielded a tamper-evident, insider-resistant database design of healthcare systems that is required to operate under scarce resources and regulatory constraints.