Secure Distributed Systems Using Quantum Communication Channels

Abstract

Distributed systems -- spanning cloud computing, edge networks, and federated databases -- rely on classical cryptographic channels whose security rests on computational hardness assumptions increasingly threatened by advances in quantum computing. Quantum communication channels, exploiting photon entanglement and the no-cloning theorem, offer information-theoretically secure alternatives that can harden distributed architectures against both classical and quantum adversaries. This paper proposes the Quantum-Secured Distributed Architecture (QSDA) framework, which integrates quantum communication channels -- specifically Quantum Key Distribution (QKD), quantum secret sharing (QSS), and quantum Byzantine agreement (QBA) -- into five canonical distributed system primitives: authenticated broadcast, distributed consensus, secret sharing, leader election, and distributed locking. QSDA is evaluated through protocol simulation across 8, 16, and 32-node distributed systems under four threat models: passive eavesdropper, active man-in-the-middle, Byzantine faulty nodes (up to f = n/3), and quantum adversary. Results demonstrate that QSDA achieves information-theoretic security for authenticated broadcast and secret sharing, reduces Byzantine consensus round complexity from O(n2) to O(n log n) using quantum channels, and maintains system throughput within 18.4% of classical baseline despite quantum channel overhead. The study contributes the QSDA specification, a Quantum-Distributed Security Index (QDSI), and a protocol integration reference for quantum-secured distributed system design.