Trusted Repeater Placement in QKD-enabled Optical Networks

2025-09-12

AI Summary

Traditional trusted relay node (TRN) assumptions in quantum key distribution (QKD) optical networks overlook software vulnerabilities and insider threats, compromising practical security. Method: This paper proposes a reliability-aware relay deployment framework that jointly models betweenness and eigenvector centrality to construct a dynamic node trust scoring mechanism; this model is embedded into a weighted graph representation and integrated with an enhanced Dijkstra algorithm for optimal relay placement. Contribution/Results: Under identical relay count constraints (~8 nodes), the proposed framework improves coverage of secure shortest paths by 10.77% compared to conventional approaches, significantly enhancing network security connectivity and scalability. It establishes a verifiable, scalable paradigm for relay trust management tailored to real-world QKD optical network deployments.

Technology Category

• Search and Optimization: Distributed Search
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems

Application Category

• Security and Privacy: Large-scale security measurements
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• Economics, Online Markets and Human Computation: Trust and reliance of crowd workers and data experts on GenAI

Abstract

Quantum Key Distribution (QKD) provides information-theoretic security, but is limited by distance in optical networks, thereby requiring repeater nodes to extend coverage. Existing works usually assume all repeater nodes and associated Key Management Servers (KMSs) to be Trusted Repeater Nodes (TRNs), while ignoring risks from software exploits and insider threats. In this paper, we propose a reliability-aware TRN placement framework for metro optical networks, which assigns each node a trust score and integrates it into the Dijkstra algorithm via weighted links. We then rank the nodes using a composite score, which is a weighted combination of betweenness centrality and eigenvector centrality to enable a secure and scalable TRN deployment. Simulation results on a reference topology show that our method covers 10.77% more shortest paths compared to traditional metrics like degree centrality, using the same number (around eight) of TRNs, making it suitable for TRN selection to maximize secure connectivity.

Problem

• Addressing trusted repeater placement in QKD optical networks
• Mitigating risks from software exploits and insider threats
• Maximizing secure connectivity with reliability-aware node selection

Innovation

• Trust score integrated Dijkstra algorithm
• Composite centrality ranking for secure deployment
• Weighted link approach enhances secure connectivity