After it was revealed that the NSA and GCHQ are able to decode encrypted data, a new system that allows messages to be sent with ‘complete secrecy’ could be on the verge of exploding into every day life.
A team of British scientists has discovered a way to build communications networks with a system called quantum cryptography, and at a larger scale than ever before. It has the potential to transform the way sensitive data is protected.
The system is based on a communication system, where information is carried by individual photons, and once they are observed then they change, therefore they cannot be intercepted by a ‘snooper’ without leaving a detectable trace or ‘footprint’.
Until now, implementing a quantum cryptography network had required a new fibre and an elaborate photon detector for each additional user that was added to the network, and this was at considerable expense.
The team working on the technology says they have now extended the way to send uncrackable codes – referred to as "quantum key distribution" (QKD) – beyond very niche applications.
Andrew Shields of Toshiba’s Cambridge Research Laboratory and colleagues, have demonstrated that up to 64 users can share a fibre link and detector.
Encrypting information on individual photons of light has the "unique virtue that it allows the secrecy of the communication to be tested", said Dr Shields.
"Now we can connect multiple users up to one single fibre and allow them to share a connection to a quantum network.
"The advantage of that is we can now build quantum networks with many more users than has been possible in the past, which also reduces the cost per user," he told BBC News.
The team has said their research could make QKD far more practical, and a lot closer to becoming a widespread technology that could be used by businesses and banks.
But Dr Huevel explained that at the moment the technology was still mainly lab-based with highly specialised people operating the technology.
"The aim is to go away from this to make it much user friendly and cheaper. This new research is one step closer, it’s the last step between the end user and a proper network," Dr Huebel added.
However, there are some that disagree with the claim that total security can be achieved with quantum cryptography.
Karl Svozil, a theoretical physicist at the Vienna University of Technology, Austria, said the protocol used in the current work was not secure against all eavesdropping methods and required that the classical channel must be uncompromised for quantum cryptography to work.
"The condition of quantum cryptography relies on certain rules that need to be obeyed – only then is it unconditionally safe. The newly proposed protocol is ‘breakable’ by middlemen attacks."
