While QKD ensures information-theoretic security at the link level, real-world deployments depend on trusted repeaters, creating potential vulnerabilities. In this paper, we thus introduce a topology-hiding connectivity assurance protocol to enhance trust in quantum key distribution (QKD) network infrastructures. Our protocol allows network providers to jointly prove the existence of a secure connection between endpoints without revealing internal topology details. By extending graph-signature techniques to support multi-graphs and hidden endpoints, we enable zero-knowledge proofs of connectivity that ensure both soundness and topology hiding. We further discuss how our approach can certify, e.g., multiple disjoint paths, supporting multi-path QKD scenarios. This work bridges cryptographic assurance methods with the operational requirements of QKD networks, promoting verifiable and privacy-preserving inter-network connectivity.

翻译：尽管量子密钥分发（QKD）在链路层面确保了信息论安全性，但实际部署依赖于可信中继节点，这引入了潜在漏洞。为此，本文提出一种拓扑隐藏的连通性保障协议，以增强量子密钥分发网络基础设施的可信度。该协议允许网络运营商在不暴露内部拓扑细节的前提下，共同证明端点间安全连接的存在性。通过将图签名技术扩展以支持多图结构与隐藏端点，我们实现了确保可靠性与拓扑隐藏性的连通性零知识证明。进一步地，我们探讨了该方法如何验证如多路径不相交路径等场景，从而支持多路径QKD应用。本文工作将密码学保障方法与QKD网络的运行需求相衔接，推动了可验证且隐私保护的互联网络连通性建设。