A FAULT-TOLERANT ADAPTIVE CRYPTOGRAPHIC FRAMEWORK FOR RELIABLE COMMUNICATION IN HYBRID QUANTUM-CLASSICAL ENVIRONMENTS

Abstract

Quantum computing poses a significant threat to contemporary cryptographic systems, particularly during the transitional phase where classical and post-quantum cryptographic algorithms coexist. Existing research has extensively analyzed the theoretical risks associated with quantum attacks; however, limited attention has been given to the engineering resilience of cryptographic systems under partial failure conditions. This paper addresses this limitation by proposing a fault-tolerant adaptive cryptographic framework designed to maintain secure communication in hybrid quantum–classical environments. The proposed framework introduces redundancy-aware encryption layers, adaptive algorithm switching, and failure detection mechanisms that respond dynamically to cryptographic degradation, key compromise, or partial quantum attacks. Unlike purely cryptographic or policy-oriented approaches, this study focuses on system-level reliability and engineering robustness. A simulation-based evaluation is conducted to analyze system behavior under multiple failure scenarios, including algorithm compromise and key exposure events. The results demonstrate that the proposed framework significantly improves communication continuity, reduces system downtime, and preserves security guarantees during transitional quantum threat conditions. This work contributes an engineering-focused solution that bridges the gap between theoretical quantum threat analysis and practical, fault-tolerant cryptographic system design, providing a resilient pathway toward secure communication in the quantum era.