Quantum key distribution with finite resources: Taking advantage of quantum noise

TL;DR

This paper analyzes how different noise scenarios, including deliberate quantum noise addition, can enhance finite key rates in quantum key distribution protocols like BB84 and six-state, especially when realistic channel noise is considered.

Contribution

It demonstrates that deliberate quantum noise and realistic channel noise assumptions can significantly improve finite key rates in QKD protocols.

Findings

Quantum noise addition benefits finite key rate.

Realistic channel noise increases secret key rate.

Comparison with classical noise and asymptotic limits.

Abstract

We compare the effect of different noise scenarios on the achievable rate of an epsilon-secure key for the BB84 and the six-state protocol. We study the situation where quantum noise is added deliberately, and investigate the remarkable benefit for the finite key rate. We compare our results to the known case of added classical noise and the asymptotic key rate, i.e. in the limit of infinitely many signals. As a complementary interpretation we show that under the realistic assumption that the noise which is unavoidably introduced by a real channel is not fully dedicated to the eavesdropper, the secret key rate increases significantly.