Eavesdrop-proof with particles of light: QuNET switches on cross-state quantum network
German research minister Bär switched on the QuNET network linking Bavaria, Thuringia and Berlin. It aims to protect communications against future quantum computers – but the technology is still costly.
Archive image · Photo: Gerd Seidel (User:Rob Irgendwer) / Wikimedia Commons, CC BY-SA 3.0 (cropped and resized)
German Federal Research Minister Dorothee Bär (CSU) has activated the QuNET initiative's first quantum communication network spanning several German states, at an event at the Futurium in Berlin. It links regional networks in Bavaria, Thuringia and Berlin; the initiative is coordinated by the Fraunhofer Institute for Applied Optics and Precision Engineering (IOF) in Jena. The aim is to protect confidential communications against future quantum computers that could break today's encryption.
The network uses quantum key distribution: keys are transmitted with particles of light, and any eavesdropping attempt is detected. In that case, the key is treated as compromised and replaced if necessary, explained QuNET spokesperson Andreas Tünnermann. Keys were already exchanged over a 75-kilometre fibre link between Jena and Erfurt in 2022. Researchers spent seven years on the project, funded by the federal government with 125 million euros, which now concludes; 44 million euros are earmarked for the core consortium's next phase.
There are limits: the technology protects only the key exchange, not computers or software, and fibre links can be disturbed even by vibrations from passing lorries. Tünnermann acknowledged that the technology is still expensive and complex. Results from the connected network are to be evaluated in the coming months. Bär believes quantum communication could be established in Germany by 2030, while calling the goal ambitious herself.