World's largest quantum-encrypted network unveiled

The world's largest quantum-encrypted network has been unveiled in Vienna, providing a glimpse of how data could be transmitted securely in the future.

The network is the result of more than four years of work with 41 organisations from 12 countries working to integrate quantum cryptography into a modern business network.

The project has been overseen by the EU-sponsored SECOQC (Development of a Global Network for Secure Communication Based on Quantum Cryptography).

Quantum cryptography is a technique of sending information in a way that makes it impossible for people to intercept without corrupting the information in transit.

Packages of data are sent down fibre-optic cables in the form of particles of light — or photons — which are then received and converted back into data.

If this data is intercepted en route, the intended recipient will see an increase in the error rate of the data received, allowing them to detect whether it has been accessed.

In the past, quantum cryptography has only really focused on point-to-point connections, but the network — which is operated by the University of Vienna — has developed the concept by using a series of nodes each with three fibre connections to other nodes.

Speaking to ZDNet.co.uk's sister site, silicon.com, Hannes Hüebel, a post-doctoral researcher who has worked on the project for four years, said: "The problem with quantum cryptography is that long distance is difficult to bridge."

He added that photons leaking from the fibre-optic cable over longer distances mean data becomes corrupted, while single connections mean data can be lost if a cable is cut. The Vienna project has tackled the problem by designing the network so that if one cable is cut, the data can be rerouted to reach the same destination.

Voice over IP and videoconferencing data is being transmitted over the network which uses existing optical fibre connections owned by tech giant Siemens.

Hüebel said the network is really about bringing the technology out of the labs and showing that it could have a genuine commercial use — such as transmitting banking and government data.

He added the aim of the project is firstly to create a viable network using the technology but also to demonstrate that it could be reliable over a period of time.

He predicts there could be "some sort of deployment" of the technology in the next five years but said this may need to be prompted by a major breach of traditional security technology or by a big commercial organisation adopting it to boost its security credentials.

"It's really hard to predict when it really will take off," Hüebel added.

The network was unveiled as part of an international conference on quantum cryptography in Vienna and will operate for several weeks until Siemens takes back its network.

Researchers at HP Labs in Bristol have also been looking at how they can use photons to transmit data to combat the theoretical threat of quantum computers.