Efficiency of coherent-state quantum cryptography in the presence of loss: Influence of realistic error correction

Abstract

We investigate the performance of a continuous-variable quantum key distribution scheme in a practical setting. More specifically, we take a nonideal error reconciliation procedure into account. The quantum channel connecting the two honest parties is assumed to be lossy but noiseless. Secret key rates are given for the case that the measurement outcomes are postselected or a reverse reconciliation scheme is applied. The reverse reconciliation scheme loses its initial advantage in the practical setting. If one combines postselection with reverse reconciliation, however, much of this advantage can be recovered.