University College London researchers have developed a new approach that ensures secure communication between three or more quantum devices.
The new development could help herald a large-scale, unhackable quantum network system unlike any seen today.
With communication via quantum networks been possible only between two devices till date, there has been a growing need to build a secure, large-scale network between cities that works for any quantum device.
“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,” explained lead author, Dr Ciarán Lee.
Funded by the UK’s Engineering and Physical Sciences Research Council (EPSRC), the study by UCL, the University of Oxford and the University of Edinburgh scientists details a new way of communicating securely between three or more quantum devices, irrespective of who built 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 Oxford University’s Dr Matty Hoban.
The approach tests the security of the quantum devices prior to engaging in communications with the whole network. It does this by checking if the correlations between devices in the network are intrinsically quantum and cannot have been created by another means.
These correlations are used to establish secret keys which can be used to encrypt any desired communication. Security is ensured by the unique property that quantum correlations can only be shared between the devices that created them, ensuring no hacker can ever come to learn the key.
Making use of machine learning and causal inference, UCL’s approach distributes secret keys in a way that cannot be effectively intercepted, because through quantum mechanics their secrecy can be tested and guaranteed.
Image and content: University College London