Reverse Reconciliation Continuous Variable Quantum Key Distribution Based on the Uncertainty Principle

TL;DR

This paper proves security for a reverse reconciliation continuous variable quantum key distribution protocol over distances exceeding 16 km, using an uncertainty relation with quantum memories, addressing previous limitations of transmission distance.

Contribution

It extends security proof techniques to reverse reconciliation protocols with quantum memories, enabling longer-distance quantum key distribution.

Findings

Security against coherent attacks over 16 km distance

Validation of the uncertainty relation with quantum memories in security proofs

Clarification of limitations in current security proof methods

Abstract

A big challenge in continuous variable quantum key distribution is to prove security against arbitrary coherent attacks including realistic assumptions such as finite-size effects. Recently, such a proof has been presented in [Phys. Rev. Lett. 109, 100502 (2012)] for a two-mode squeezed state protocol based on a novel uncertainty relation with quantum memories. But the transmission distances were fairly limited due to a direct reconciliation protocol. We prove here security against coherent attacks of a reverse reconciliation protocol under similar assumptions but allowing distances of over 16 km for experimentally feasible parameters. We further clarify the limitations when using the uncertainty relation with quantum memories in security proofs of continuous variable quantum key distribution.