The first network protected by quantum encryption has gone live at a scientific conference in Vienna.

The network comprises six systems and eight intermediary links across Vienna and St Pöelten linked by over 200km of fibre-optic cable.

The links use six different quantum cryptographic technologies for key generation which are integrated into the network using standardised tools.

The network was set up by the Secure Communication based on Quantum Cryptography group, which was set up in 2004 to build technologies that could counter espionage, in particular from the Echelon surveillance system run by the UK, the US, Canada, Australia and New Zealand.

"We will provide a tool based on quantum technologies which will enable economical enterprises to guard their assets against industrial espionage," said Dr Christian Monyk, the initiator of the project.

"In the past, significant financial losses due to industrial espionage had to be attributed to activities of the Echelon communication surveillance and interception network.

"Our aim is to make a significant contribution to the independence and competitiveness of the European economy."

Nodes for each point of the network have been set up in Siemens offices since the company did much of the work on the project.

The nodes are standardised 19in boxes containing mobile quantum cryptographic devices that can be linked to standard network architecture.

The European Union has invested €11m in the project so far, which was set up after EU investigations into claims that the Echlon system was used to spy on European companies to gain a business advantage. The UK and US denied the claims.

The quantum cryptography systems rely on an application of the Heisenberg Uncertainty Principle, which broadly states that it is impossible to observe quantum information without altering it.

This makes eavesdropping impossible, since as soon as it takes place the change in data can be recognised and the network shut down.