Quantum network: Secure data transmission on the internet of the future
07/14/2026How could a flexible and efficient quantum network help to safeguard communication against the threat posed by future quantum computers? A collaborative project involving the University of Würzburg is investigating this question.
The fibre-optic network reliably transmits enormous volumes of data using light signals, but faces technical limitations when it comes to security and protection against eavesdropping. A quantum network takes this a decisive step further: it utilises the laws of quantum physics to fundamentally protect information from undetected access. Quantum networks could be used by governments, public authorities, and in the healthcare and financial sectors.
Quantum networks could provide permanent security for data transmission. Much of today’s communication is at risk: increasingly sophisticated, powerful quantum computers already pose a threat. Data currently being transmitted can be stored and decoded in the future. In addition to terrestrial networks, satellites could help bridge greater distances, but they are costly and dependent on daylight and weather conditions.
A new collaborative project is now working on a secure and efficient solution. The aim is to establish interconnected, local quantum domains that enable secure data transmission over long distances.
Guido Dietl, holder of the Professorship of Computer Science (Satellite Communication and Radar Systems) at Julius-Maximilians-Universität Würzburg (JMU), is involved in the project. The sub-project is being funded with more than 580,000 euros by the Federal Ministry of Research, Technology and Space (BMFTR).
A long-term solution for secure data transmission
The starting point: much of today’s data traffic is secured using current cryptographic methods. “Quantum computers are developing at a rapid pace and, together with existing quantum algorithms, pose a threat to precisely these systems,” says Dietl. At present, the only thing missing is a quantum computer with sufficient processing power to execute the algorithms. In the long term, therefore, a different solution is needed: methods based on quantum mechanics and post-quantum cryptography (PQK).
Some telecommunications companies are already using PQK to protect data traffic from quantum computers. Although these methods are standardised, they are not yet particularly widespread. The alternative is quantum key distribution (QKD): “This method makes a network eavesdropping-proof and detects eavesdropping attempts within the domain,” explains the JMU computer scientist.
The problem with this form of encryption currently lies in the signal’s range, which is only a few hundred kilometres. Whilst additional trusted nodes help to bridge long distances, they make the network vulnerable to attacks. “So-called Twin-Field QKD could extend the range without the need for trusted nodes,” says Dietl.
Focus on domain transitions
The Würzburg sub-project is developing strategies for how new methods of secure key distribution – such as Twin-Field QKD or satellite-based solutions – can be used to connect quantum domains. “One key focus is on what the quantum-secure transition from one domain – that is, from a locally limited network area – to another might look like,” explains the Würzburg professor.
The JMU computer scientist is also working on a suitable post-processing method for the test system: the main aim here is to detect and correct errors in Twin-Field QKD. Finally, a demonstration of a QKD domain with two nodes is to be carried out in Würzburg in collaboration with the software company Infosim – which was founded over 20 years ago as a spin-off from JMU – and the other consortium partners.
About the collaborative project
The collaborative project “Quantum Domain Dynamics (QDD)” is funded by the BMFTR with just under 3.83 million euros under the funding scheme “Secure Use of Quantum Communication in Applications”. The funding has been in place since 1 June 2026 for a period of three years. In addition to JMU, the other consortium partners are:
- Infosim GmbH & Co. KG, Würzburg (consortium coordinator)
- Quant-X Security & Coding GmbH
- Telefonica Germany GmbH & Co. OHZ
- Fraunhofer Institute for Applied Optics and Precision Engineering (IOF)
- Friedrich-Schiller-Universität Jena
- Friedrich-Alexander-Universität Erlangen-Nuremberg
Contact
Prof. Dr Guido Dietl, Professorship of Computer Science (Satellite Communication and Radar Systems), Institute of Computer Science, T +49 931 31-80080, guido.dietl@uni-wuerzburg.de
