An ultra-high security scheme that could one day get quantum cryptography using Quantum Key Distribution into mobile devices has been developed and demonstrated by researchers from the University of Bristol’s Centre for Quantum Photonics (CQP) in collaboration with Nokia.

Secure mobile communications underpin our society and through mobile phones, tablets and laptops we have become online consumers. The security of mobile transactions is obscure to most people but is absolutely essential if we are to stay protected from malicious online attacks, fraud and theft.

Currently available quantum cryptography technology is bulky, expensive and limited to fixed physical locations – often server rooms in a bank. The team at Bristol has shown how it is possible to reduce these bulky and expensive resources so that a client requires only the integration of an optical chip into a mobile handset.

The scheme relies on the breakthrough protocol developed by CQP research fellow Dr Anthony Laing, and colleagues, which allows the robust exchange of quantum information through an unstable environment. The research is published in the latest issue of Physical Review Letters.

Dr Laing said: “With much attention currently focused on privacy and information security, people are looking to quantum cryptography as a solution since its security is guaranteed by the laws of physics. Our work here shows that quantum cryptography need not be limited to large corporations, but could be made available to members of the general public. The next step is to take our scheme out of the lab and deploy it in a real communications network.”

The system uses photons – single particles of light – as the information carrier and the scheme relies on the integrated quantum circuits developed at the University of Bristol. These tiny microchips are crucial for the widespread adoption of secure quantum communications technologies and herald a new dawn for secure mobile banking, online commerce, and information exchange and could shortly lead to the production of the first 'NSA proof' mobile phone.

Paper:

'Reference frame independent quantum key distribution server with telecom tether for on-chip client' by P. Zhang, K. Aungskunsiri, E. Martín-López, J. Wabnig, M. Lobino, R. W. Nock, J. Munns, D. Bonneau, P. Jiang, H. W. Li, A. Laing, J. G. Rarity, A. O. Niskanen, M. G. Thompson, J. L. O'Brien in Physical Review Letters, 2 April 2014.

This work was supported by EPSRC, ERC, QUANTIP, PHORBITEC, and NSQI. P.Z. acknowledges support from the Fundamental Research Funds for the Central Universities and the National Natural Science Foundation of China (Grants No. 11004158 and No. 11374008). J. M. acknowledges EPSRC Grant Code No. EP/G036780/1. J. L. OB. acknowledges a Royal Society Wolfson Merit Award and a Royal Academy of Engineering Chair in Emerging Technologies.

The Centre for Quantum Photonics is a pioneering research group in the area of Quantum Technologies. It has over 70 members and a grant portfolio of greater than £20million. Having invented the integrated quantum photonic chip it has already made publically accessible and available online a real quantum computer 'quantum in the Cloud' for the purposes of educating those interested in future quantum computing technologies.