Round-robin differential-phase-shift quantum key distribution with a passive decoy state method

Li Liu,Su-Juan Qin,Qiao-Yan Wen,Fen-Zhuo Guo

doi:10.1038/srep42261

Li Liu, Su-Juan Qin + Show 2 more

Open Access

https://doi.org/10.1038/srep42261

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Abstract

Recently, a new type of protocol named Round-robin differential-phase-shift quantum key distribution (RRDPS QKD) was proposed, where the security can be guaranteed without monitoring conventional signal disturbances. The active decoy state method can be used in this protocol to overcome the imperfections of the source. But, it may lead to side channel attacks and break the security of QKD systems. In this paper, we apply the passive decoy state method to the RRDPS QKD protocol. Not only can the more environment disturbance be tolerated, but in addition it can overcome side channel attacks on the sources. Importantly, we derive a new key generation rate formula for our RRDPS protocol using passive decoy states and enhance the key generation rate. We also compare the performance of our RRDPS QKD to that using the active decoy state method and the original RRDPS QKD without any decoy states. From numerical simulations, the performance improvement of the RRDPS QKD by our new method can be seen.

Highlights

In this paper, we apply the passive decoy state method to the RRDPS Quantum key distribution (QKD) protocol
A performance improvement of our RRDPS QKD using passive decoy state method can be seen in numerical simulations
The protocol proceeds as follows: 1. Alice uses two weak coherent pulses with random phases to passively generate signal or decoy states. In this way she can prepare a series of pulse trains with each contains L pulses, and each train encodes a random L-bit sequence s = (s1s2...sL) on a weak signal

Summary

Introduction

We apply the passive decoy state method to the RRDPS QKD protocol. Alice uses weak coherent sources with random phases to passively generate signal states or decoy states. A performance improvement of our RRDPS QKD using passive decoy state method can be seen in numerical simulations.

Results

Conclusion