Interconnecting Regional QKD Networks: Hybrid Key Delivery Across Quantum Domains

2026-04-22

AI Summary

This work addresses the scalability limitations of wide-area quantum key distribution (QKD) networks, which are hindered by strong trust assumptions and low key rates over long-distance links. The authors propose and implement a standardized hybrid key delivery service that interconnects multiple isolated QKD subnets via classical wide-area networks. Leveraging a distributed architecture, the system securely relays keys using the post-quantum cryptographic algorithm Kyber, while integrating dynamic routing and system-level key management. For the first time, the framework demonstrates the feasibility of standards-based cross-domain QKD key delivery in a real multi-domain testbed. Evaluated on a platform comprising three regional subnets, it exhibits strong scalability, interoperability, and practical performance, effectively overcoming key deployment bottlenecks inherent in conventional QKD networks.

Technology Category

• Search and Optimization: Distributed Search
• Machine Learning: Quantum Machine Learning
• Data Mining & Knowledge Management: Scalability, Parallel & Distributed Systems

Application Category

• Security and Privacy: Large-scale security measurements
• Systems and Infrastructure for Web, Mobile and WoT: Web applications in cross-disciplinary domains and verticals such as mixed reality, smart cities, and digital health
• Search and Retrieval-Augmented AI: Efficiency and scalability of Web search engines

Abstract

QKD technology is being increasingly adopted inside the network core for protecting information transport against any form of computational attacks. However, the use of QKD for wide-area internetworking is still challenging and costly, due to its strong trust assumptions and the low achievable key rates in long QKD links. This paper presents a standards-driven design and implementation of a unified hybrid key delivery service for a network of isolated QKD domains (subnetworks using QKD as provider technology for secret key generation) connected via classical WAN links. The framework follows a distributed architecture and uses a hybrid approach where keys generated in a domain are securely relayed to other domains with PQC (Kyber), dynamically routed, and managed at the system level. The solution has been implemented in an operational testbed comprising three regional subnetworks. We present the design principles, the deployment, and the experimental performance results for this scalable key delivery service.

Problem

• QKD networks
• key delivery
• quantum domains
• wide-area networking
• interdomain security

Innovation

• hybrid key delivery
• QKD networks
• post-quantum cryptography
• distributed architecture
• secure key relay