Topology-Hiding Connectivity-Assurance for QKD Inter-Networking

2026-04-02

AI Summary

Current quantum key distribution (QKD) networks rely on trusted relays, introducing inherent security vulnerabilities and lacking mechanisms to verify end-to-end secure connectivity without disclosing internal network topology. This work proposes a topology-hiding connectivity assurance protocol that extends graph signature techniques to multi-graph settings with concealed endpoints, thereby enabling, for the first time, a zero-knowledge proof of QKD network connectivity. The approach accommodates complex topologies—including multipath routing—and allows reliable verification of multiple disjoint secure paths while preserving network privacy, effectively fulfilling the verifiable interconnection requirements of multipath QKD networks.

Abstract

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.

Problem

• QKD networking
• trusted repeaters
• topology hiding
• connectivity assurance
• quantum key distribution

Innovation

• topology-hiding
• zero-knowledge proof
• quantum key distribution
• graph signature
• multi-path QKD