Security proof for single-photon round-robin differential-quadrature-phase-shift quantum key distribution
Rong Wang, Zhen−Qiang Yin, Chaohan Cui, Shuang Wang, Wei Chen, Guang‐Can Guo, Zheng‐Fu Han · Physical Review A · 2018
Combining the differential-quadrature-phase-shift (DQPS) quantum key distribution (QKD) protocol and the recently proposed round-robin-differential-phase-shift (RRDPS), the round-robin-differential-quadrature-phase-shift (RRDQPS) protocol has been proposed. However, a security proof of the RRDQPS QKD protocol is still missing and its advantage over the original RRDPS protocol is also unknown. Here, we give the security proof of single-photon RRDQPS protocol, by which we clearly show that, if a single photon source is applied, RRDQPS protocol will overwhelm the original RRDPS protocol in terms of tolerable error rate. More interestingly, our proof gives a unified theory covering the well-known Bennett-Brassard 1984 (BB84) protocol and RRDQPS protocol. Thus, it is confirmed that BB84 protocol is indeed a special case of the RRDQPS protocol.