SARG04 decoy-state quantum key distribution based on an unstable source

周媛媛, 周学军

为 SARG04 圈套状态量钥匙分发(QKD ) 的一个三状态的协议基于不稳定的来源被介绍。没有使用原来的圈套状态想法的基本假设，到安全关键产生率的更低的界限被导出。与不稳定的参量的下面变换来源一起的三状态的 SARG04 圈套状态协议在模拟被考虑。在与不稳定的来源一起的这份报纸的协议给关键产生率那的模拟结果表演与稳定的来源一起接近那，并且当传播距离长时，仅仅细微的优点由使用稳定的来源出现。与不稳定的来源一起的 SARG04 圈套状态协议能仍然因此用一把稍微弄短的最后的钥匙获得无条件的安全。

Yi Zhao, Hoi‐Kwong Lo, Xiongfeng Ma +3 more

Wang, Chen, GUILHERME BARRETO XAVIER +7 more

Yuanyuan Zhou, Xuejun Zhou, Jun Yao Gao

Decoy states have recently been proposed as a useful method for substantially improving the performance of quantum key distribution (QKD). Considering the Scarani-Acin-Ribordy-Gisin protocol (SARG04) with a heralded single photon source (HSPS), we review the general model of HSPS QKD system with a threshold detector, and analyze the SARG04 non-decoy-state protocol, SARG04 infinite active decoy-state protocol and SARG04 decoy-state protocol combining active decoy state method and passive decoy state method. Furthermore, we discuss the choice of optimal signal intensity for HSPS QKD with and without decoy states and obtain the condition that the optimal signal intensity satisfies. The simulation and analysis results show that the decoy state method can substantially improve the performance of SARG04 protocol with HSPS and the performance of SARG04 protocol with HSPS is better than that of BB84 protocol with HSPS. The decoy state method weakens the dependence of the optimal signal intensity on the overall transmission probability.

Sellami Ali

Kang Liu, Jie Wei, Chun-Mei Zhang +1 more

We present a new scheme for realizing passive decoy-state quantum key distribution with the SARG04 protocol. It is based on parametric down-conversion sources, and we do not need to modulate the pumping light into different intensities. By applying local-mode-splitting detections on Alice’s side, legitimate users can obtain four different kinds of counting events on Bob’s side, due to intrinsic correlations between photon pairs from parametric down-conversion processes. In the new scheme, we do not need to modulate signal pulses into different intensities and can, thus, avoid introducing any intensity modulating uncertainty. As a result, quite precise estimations of single- or multi-photon-pulse contributions can be obtained, enabling better performance of the key generation rate and transmission distance compared with other existing SARG04 protocols, e.g., the four-intensity decoy-state method using either parametric down-conversion sources or weak coherent sources. Besides, through comparisons, we also find that the proposed new passive decoy-state SARG04 protocol can also show some superiority over the conventional three-intensity decoy-state BB84 protocol at long transmission distances under certain experimental conditions.