Round-robin-differential-phase-shift quantum key distribution with monitoring signal disturbance.

In recent years, round-robin-differential-phase-shift (RRDPS) quantum key distribution (QKD) has attracted great attention for its unique characteristics, i.e., the information leakage can be bounded without learning bit error rate. Though the RRDPS QKD has made a breakthrough, it is still a question of how RRDPS will perform with monitoring signal disturbance, e.g., decoy-state and error rate statistics are both used. Here, we present simulations to study RRDPS protocol while monitoring signal disturbance. To our excitement, when using the infinite decoy-states method, RRDPS protocol can outperform the commonly used Bennett and Brassard 1984 (BB84) protocol in terms of channel length under typical experimental parameters. In the case of finite decoy states, we find that only two decoy-states and one signal state are sufficient to obtain performance very close to the infinite decoy-states case. Our simulations prove that RRDPS is a competitive protocol in real-life situations.