The networked world is increasingly being shaken by digital sabotage, cyber attacks, malware and the like. Yet IT security is more important than ever these days. Networks based on quantum physics could significantly improve the security of relevant systems. So-called quantum repeaters form the basis for this. These devices have been the subject of intensive research for several years, but are not yet marketable. A new joint project, in which Paderborn University is involved, therefore aims to develop new concepts and demonstrate them on real test tracks outside the laboratory.