UCL researchers develop method for securing communications between quantum computers

Scientists claim that technique could make quantum communications unhackable

University College London (UCL) scientists claim to have devised a new method for securing communication between multiple quantum devices.

They claim that their finding represents a major step forward for the introduction of a "large-scale, unhackable quantum network" which will dominate technology of the future.

Up until now, there's been little research exploring communication over quantum networks. And previous findings have focused on what's possible between two devices.

The EU and UK governments have already unveiled plans to invest €1 billion and £270 million into researching quantum computing technology. According to the UCL researchers, there's a race to develop the world's first "secure, large-scale network between cities" in the EU, although China already claims to have a network up and running.

Lead author Dr Ciarán Lee, who specialises in physics and astronomy at UCL, said: "We're in a technology arms race of sorts. When quantum computers are fully developed, they will break much of today's encryption whose security is only based on mathematical assumptions.

"To pre-emptively solve this, we are working on new ways of communicating through large networks that don't rely on assumptions, but instead use the quantum laws of physics to ensure security, which would need to be broken to hack the encryption."

The project was published in Physical Review Letters and funded by the Engineering and Physical Sciences Research Council. The University of Oxford and the University of Edinburgh also took part in the study.

The scientists created a new approach that "bridges the gap between the theoretical promise of perfect security guaranteed by the laws of quantum physics and the practical implementation of such security in large networks".

Another groundbreaking finding is that this approach is capable of testing the security of quantum devices before they communicate. Instead, they can first look for any correlations between them.

"Our approach works for a general network where you don't need to trust the manufacturer of the device or network for secrecy to be guaranteed. Our method works by using the network's structure to limit what an eavesdropper can learn," said Dr Matty Hoban, from the University of Oxford.

Dr Lee added: "Our work can be thought of as creating the software that will run on hardware currently being built to realise the potential of quantum communications.

"In future work, we'd like to work with partners in the UK national quantum technologies programme to develop this further. We hope to trial our quantum network approach over the next few years."