<p>The rapid evolution of distributed systems has brought up a critical demand for robust security frameworks capable of resisting advanced cyber threats. Quantum key Distribution (QKD), facilitated by the laws of quantum mechanics is an emerging technology that promises theoretically unbreakable encryption. This paper proposes an advanced security architecture integrating QKD with distributed system communication protocols in order to ensure end-to-end data confidentiality and integrity. Therefore, this study discusses the issues of practical key management, scalability, and interoperability in a heterogeneous setting. Recent findings in the areas of quantum-resistant algorithms and hybrid classical quantum cryptographic protocols have been leveraged to increase the resistance against quantum-capable adversaries. The simulation results showed substantial gains in latency, fault tolerance, and security metrics. Therefore, this work is future-proof, as it shows the way ahead for secure communication in imminent quantum advancements in computing.</p>