Sorbonne and Edinburgh researchers authenticate quantum keys using entanglement

[Sophie83]

Quantum key distribution has a chicken and egg problem, and researchers may have found a way around it. Quantum Zeitgeist reports on work by Nicolas Laurent-Puig, Mina Doosti, Adriano Innocenzi and Eleni Diamanti from Sorbonne Université and the University of Edinburgh that removes the need for a pre shared secret to authenticate the first connection

Normally, quantum key distribution needs an authenticated classical channel, which requires the two sides to already share a secret key. The team uses what it calls a hybrid entangled physical unclonable function to generate the first secure key, so authentication does not depend on a secret exchanged in advance

In tests, the quantum bit error rate stayed below 0.6 percent, and keys were distributed through up to 50 decibels of channel loss using a telecom wavelength entangled photon source

The authors describe it as the first demonstration of its kind, to their knowledge. Throughput is currently limited by the speed of a mechanical actuator in the setup

Removing the need for pre shared secrets would make quantum key distribution much easier to deploy between parties who have never met. Tolerating 50 decibels of loss is impressive and suggests long distance potential. Faster hardware should solve the throughput limit over time

Could this make quantum key distribution practical for everyday use? And how important is authentication in quantum security?

A New Quantum Authentication Method Relies On Entanglement, Not Pre-shared Keysquantumzeitgeist.com