Entanglement-assisted authenticated BB84 protocol

Inhalt:
This work delivers a novel user-server authentication procedure exploiting the features of maximally entangled pairs. Additionally, we leverage the specific features of our design, which are conveniently suited for inlaying it into the well known BB84 quantum communication protocol. We first define a trivial extension of our initial proposal allowing for such task (symmetric scheme) to then come up with what we denote as asymmetric scheme, better matching practicality. Furthermore, a realistic simulation of our user-server authentication protocol has been achieved by employing a noisy model for both transmission and storage, the latter relying on cavity-enhanced Atomic-Frequency Comb (AFC) memories. While in a noiseless scenario our proposal is ensured to be airtight, considering a certain degree of noise poses a challenge when aiming to actually implement it. We have implemented a deep neural network to distinguish legitimate users from forgery attempts, outperforming a mere statistical approach designed for the same task. Such method achieved a success rate of 0.75 with storage times of 1 mus and a user-server distance of 10 km.