Flexible and self-repairing hierarchical role-based access control for dynamic IoT systems

The rapid proliferation of Internet of Things (IoT) systems introduces stringent requirements for access control mechanisms that must operate securely under dynamic privilege changes, heterogeneous devices, and potential adversarial manipulation. Traditional role-based access control (RBAC) offers administrative simplicity but lacks adaptability in highly dynamic environments, while attribute-based approaches provide flexibility at the cost of increased policy-management and verification complexity. In security-critical IoT deployments, inconsistent role assignments or corruption of authorization metadata may directly affect system integrity, data confidentiality, and operational continuity. This paper introduces FR-HRBAC, a Flexible and Self-Repairing Hierarchical Role-Based Access Control framework for dynamic IoT systems. FR-HRBAC organizes roles and data types hierarchically and constrains derived privileges according to parent-role permissions. The framework combines continuous structural validation with authenticated recovery metadata. When a valid parent, higher ancestor, or protected $$\textrm{rootBackup}$$ remains available, a corrupted role state can be reconstructed exactly. When exact ancestor information is unavailable, FR-HRBAC can derive a conservative, non-inflating privilege state from surviving descendant information. We formally characterize hierarchy compliance, non-escalation, exact ancestor-based recovery under the stated assumptions, conservative descendant-based recovery, termination, storage overhead, and the computational complexity of validation and repair. The framework assumes that the access-control service, cryptographic keys, and independently protected $$\textrm{rootBackup}$$ remain trustworthy. Compromise of these components, denial-of-service attacks, and infrastructure-level failures are outside the current threat model. A prototype implementation was evaluated through authorization-correctness tests, corruption-rate experiments, concurrency testing, user-population scaling, storage analysis, and controlled comparisons with relate works. The results demonstrate that structural validation and authorization-metadata recovery can be integrated with low-latency authorization under the evaluated configuration. Overall, FR-HRBAC addresses a specific resilience gap in conventional hierarchical RBAC by combining controlled privilege flexibility with exact, conservative, and fail-safe responses to authorization-metadata corruption.