Security of distributed-phase-reference quantum key distribution

TL;DR

This paper provides the first comprehensive security proof for distributed-phase-reference quantum key distribution protocols, demonstrating their robustness against general attacks and revealing new key rate scaling behaviors.

Contribution

It introduces a generic security proof method for these protocols and offers lower bounds on key rates, showing quadratic scaling with transmittance.

Findings

Security proof established for distributed-phase-reference QKD

Key rate scales quadratically with transmittance

Lower bounds demonstrate protocol robustness

Abstract

Distributed-phase-reference quantum key distribution stands out for its easy implementation with present day technology. Since many years, a full security proof of these schemes in a realistic setting has been elusive. For the first time, we solve this long standing problem and present a generic method to prove the security of such protocols against general attacks. To illustrate our result we provide lower bounds on the key generation rate of a variant of the coherent-one-way quantum key distribution protocol. In contrast to standard predictions, it appears to scale quadratically with the system transmittance.