The aim of Q-Net-Q is to integrate Quantum Key distribution (QKD) in backhaul communication networks and Internet Exchange Points (IXPs) by dedicated testbeds.

Funded by Federal Ministry of Education and Research (BMBF)

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Duration: March 2023 - August 2025

The increasing demand of digital communication networks with higher bandwidth and denser networks requires new, efficient and secure communication channels given the fact that today's infrastructure is leveraged as a new attack vector in global political conflicts. In today's Internet Service Provider (ISP) network infrastructure, the technical lack of security technologies makes it difficult to achieve the goal of guaranteed, accepted and integrated security in data transmission, cryptographic key distribution, and random number generation. In an increasingly networked world, the security of digital system components has become an essential building block for the success of modern societies. Entangled quantum communication is a promising technology to guarantee security, randomization, and data transmission at a fundamental level. Therefore, the players in information and communication technologies (ICT), as operators of today's Internet network infrastructures, must combine their efforts with quantum physicists to be able to effectively guarantee secure communication in today's data networks. Digital progress, for example through Quantum Key Distribution (QKD), based on either single-qubit or entangled resources, enables the shift from cryptographic key transmission through mathematical methods of factoring large numbers to guaranteed security through fundamental physical processes of quantum mechanics. However, such quantum communication applications are hardly being used in existing telecommunications networks, because a cost-efficient technology transfer to permit system integration and long-term stability of these components in ICT networks is presently missing.

HHI is leading the deployment of a long-distance QKD-link between Berlin and Frankfurt a. Main. It will be realised by a chain of QKD point-to-point links in a so-called Trusted-Relay configuration. Hence, the QKD-keys that are generated by each individual link are cryptographically combined in a specific way by a Key Management System layer in order to establish a final secret key between the distant end points in Berlin and Frankfurt. The QKD nodes will be installed in secure sites along the fibre track, being separated from each other by around 80km. The technological cornerstone for the envisioned QKD link will be a BB84 discrete variable QKD system as currently developed by Fraunhofer HHI within the scope of the BMBF QuNET initiative. This long-distance QKD network link will serve as an exemplary testbed of future Wide-Area-QKD-Networks within EuroQCI connecting EU partners across borders. The testbed installation will support the experimental characterisation and validation of how well QKD technology scales with long distances and thereby enables new use-cases. For example, the realisation of this long-distance link and its interconnects to the adjacent networks allows the development and analysis of an architecture of open interfaces between QKD and Mobile Network Operators for 4G/5G and 6G.