Secure Decentralized Key Relaying via Random Walks in Dynamic Semi-Trusted QKD Networks

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Current QKD networks rely on trusted relay nodes to overcome distance and key-rate limits, but compromised relays and centralized controllers can expose shared keys or create single points of failure. This paper proposes a decentralized, topology-oblivious key-relay algorithm based on random walks. The algorithm provides information-theoretic security when an uncompromised path exists between each pair of nodes, offers computational security guarantees for more constrained topologies, and is evaluated using the GÉANT GN4-3N network topology.

@article{kozlovics2026secure,
  title={Secure Decentralized Key Relaying via Random Walks in Dynamic Semi-Trusted QKD Networks},
  author={Kozlovi{\v{c}}s, Sergejs and Petru{\v{c}}e{\c{n}}a, Kri{\v{s}}j{\=a}nis and Kalnina, Elina and Viksna, Juris},
  journal={Advanced Quantum Technologies},
  volume={9},
  number={8},
  pages={e70393},
  year={2026},
  doi={10.1002/qute.70393}
}