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Published on: September 8, 2023
Topology-Oblivious Random-Walk Key Relaying in Quantum Key Distribution Networks
Krišjānis Petručeņa1, Sergejs Kozlovičs1, Juris Vīksna1
1Institute of Mathematics and Computer Science, University of Latvia, LV-1459 Riga, Latvia.
Entropy (Basel, Switzerland)
|June 26, 2026
Summary
This study explores topology-oblivious stochastic forwarding for quantum key distribution (QKD) networks. It demonstrates that decentralized relaying can achieve useful security and efficiency without centralized control.
Area of Science:
- Quantum Information Science
- Network Security
- Cryptography
Background:
- Quantum key distribution (QKD) networks face challenges in managing keys between distant entities lacking direct quantum links.
- Current relay strategies often depend on centralized control or global routing information, limiting scalability and resilience.
Purpose of the Study:
- To investigate the feasibility of topology-oblivious stochastic forwarding for QKD relaying.
- To analyze the security-overhead trade-off in decentralized QKD network designs.
- To determine if local forwarding can maintain information-theoretic security (ITS).
Main Methods:
- Modeling QKD key material relaying using random-walk variants.
- Applying privacy amplification for key reconstruction.
- Evaluating performance on the GÉANT European academic backbone network topology.
- Developing and assessing a highest-score-neighbor local path-diversification heuristic.
- Implementing scouting-based loop erasure for route optimization.
Main Results:
- Different random-walk variants exhibit distinct security and efficiency characteristics.
- The proposed heuristic reduces the likelihood of compromised nodes relaying key material.
- Scouting-based loop erasure effectively shortens routes and enhances throughput.
- Stochastic forwarding shows comparable or better performance than static methods against adversarial nodes.
Conclusions:
- Topology-oblivious stochastic forwarding offers a simpler, decentralized alternative for QKD relaying.
- This approach eliminates the need for centralized orchestration or complex gossip protocols.
- Decentralized relaying can achieve practical security and efficiency in QKD networks.
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