Plug-and-play round-robin differential phase-shift quantum key distribution

Qian-Ping Mao,Le Wang,Sheng-Mei Zhao

doi:10.1038/s41598-017-15777-9

Abstract

The round-robin differential-phase-shift quantum key distribution (RRDPS-QKD) protocol could provide an effective way to estimate the leakage information without monitoring the signal disturbance. Moreover, the self-compensating property of plug-and-play (P&P) setup can eliminate the variations of phase or polarization in QKD procedure. In the paper, we introduce the P&P concept into RRDPS-QKD, and propose a QKD protocol, named P&P RRDPS-QKD protocol, to make the RRDPS-QKD scheme more practical. We analyze the security, and discuss the key generation rate with infinite-intensity decoy state method. The results show that the proposed protocol is a good solution to RRDPS-QKD protocol with untrusted sources. It has a high security and its key generation rate could be as good as the protocol with trusted sources when the average input photon number N is greater than 106. In addition, the proposed protocol has a high noise tolerance in comparison with P&P BB84-QKD protocol.

Highlights

Quantum key distribution (QKD) allows two distant parties (Alice and Bob) to share secret keys even with the existence of an eavesdropper, Eve[1]
Once the trains arrive at Alice, they are passed through an optical filter (F) and a monitoring unit, which consists of a beam splitter(BS) and an intensity detector (ID)
After being reflected by a Faraday mirror (FM), they are phase randomized by a phase randomizer (PR), and encoded by an encoder that consists of an intensity modulator (IM) and a phase modulator (PM)

Summary

Introduction

Quantum key distribution (QKD) allows two distant parties (Alice and Bob) to share secret keys even with the existence of an eavesdropper, Eve[1]. In RRDPS-QKD protocol, Alice encodes random bits in the phases of quantum signal including L pulses, named train, and sends the signal to Bob through an insecure quantum channel.

Results

Conclusion