An internet based on quantum physics will soon enable inherently secure communication. A team at Delft University of Technology, is building a network connecting four cities in the Netherlands entirely by means of quantum technology. Messages sent over this network will be unhackable.

The Delft network, will be the first to transmit information between cities using quantum techniques from end to end. The technology relies on a quantum behavior of atomic particles called entanglement. Entangled photons can’t be covertly read without disrupting their content. But entangled particles are difficult to create, and harder still to transmit over long distances. This technology has demonstrated it can send more than 1.5 kilometers, and they are confident they can set up a quantum link between Delft and the Hague by around the end of this year. Ensuring an unbroken connection over greater distances will require quantum repeaters that extend the network.

Such repeaters are currently in design at Delft and elsewhere. The first should be completed in the next five to six years with a global quantum network following by the end of the decade.

https://www.technologyreview.com/10-breakthrough-technologies/2020/