Linking QKD Testbeds across Europe

Entropy (Basel). 2024 Jan 31;26(2):123. doi: 10.3390/e26020123.

Abstract

Quantum-key-distribution (QKD) networks are gaining importance and it has become necessary to analyze the most appropriate methods for their long-distance interconnection. In this paper, four different methods of interconnecting remote QKD networks are proposed. The methods are used to link three different QKD testbeds in Europe, located in Berlin, Madrid, and Poznan. Although long-distance QKD links are only emulated, the methods used can serve as a blueprint for the secure interconnection of distant QKD networks in the future. Specifically, the presented approaches combine, in a transparent way, different fiber and satellite physical media, as well as common standards of key delivery interfaces. The testbed interconnections are designed to increase the security by utilizing multipath techniques and multiple hybridizations of QKD and post-quantum cryptography (PQC) algorithms.

Keywords: QKD; quantum communications; quantum cryptography; quantum networks.

Grants and funding

We acknowledge the support from the “MADQuantum-CM” project funded by Comunidad de Madrid (Programa de Acciones Complementarias) and by the Recovery, Transformation and Resilience Plan—Funded by the European Union—(NextGenerationEU, PRTR-C17.I1), the QUBIP project, funded by the European Union under the Horizon Europe framework program under Grant Agreement No. 101119746, QuantERA II Programme, European Union’s Horizon 2020 research and innovation program under Grant Agreement No 101017733, and with funding organizations: The Foundation for Science and Technology—FCT, Agence Nationale de la Recherche—ANR, and Spanish Agencia Estatal de Investigación—AEI, and the European Union’s Horizon Europe research and innovation funding program under the project “Quantum Secure Networks Partnership” (QSNP, grant agreement No 101114043).