MDI-QKD Enables Untappable Quantum Cryptography

Engineers at QuTech (a collaboration between Delft University of Technology and TNO) can use measurement device-independent (MDI) quantum key distribution (QKD) to provide uninterrupted communication that is scalable in terms of cost for multiple users. A remarkable side effect is that the uninterrupted communication can take place over the same fibre-optic connection as conventional internet traffic. Thanks to KPN and Cisco, a test setup could be made that put this into practice. MDI-QKD is an important step towards a quantum Internet accessible to everyone.

Demonstration in Delft-Rijswijk-Den Haag

The current set-up consists of three standard telco racks, each in a different city in the Netherlands. The first 'user' connected to the demo set-up has the code name Alice and is located in Delft. The second user, called Bob, is in a KPN building in The Hague. The central node Charlie is in between. Each user is connected to the central node via a standard glass fibre cable. In addition, the users and the central node can communicate via the normal internet, either directly via the (same) fibre-optic connection or indirectly via any internet connection.

The introduction of MDI-QKD is an important step towards the future quantum internet. The network has been designed to be future-proof. This means that users such as Alice and Bob can modernise their functionality (with, for example, quantum processors, quantum repeaters, quantum memory, quantum computers, whatever) while the central node and the rest of the network remain the same. The network is ready for the future and can be upgraded for the quantum future.

For more information (in Dutch) please read this article by KPN.