标题： BB84协议在接收者被动偏置基选择情况下的安全性 显示英文标题

标题： Security of the BB84 protocol with receiver's passive biased basis choice

摘要： BB84协议（Bennett-Brassard 1984协议）是实现量子密钥分发（QKD）的最简单协议之一。 在该协议中，发送方和接收方依次选择两个互补测量基中的一个。 关于接收方的基选择，一些实现包括卫星QKD和时间箱编码在内采用了被动设置。 然而，如果接收方以有偏概率被动地选择其测量基，然后使用阈值探测器进行测量，传统的证明BB84协议安全性的理论技术将不适用。 在此，我们为这种带有接收方被动基选择和使用阈值探测器测量的诱饵态BB84协议提供了完全分析的安全性证明。 由于分析性质，我们的安全性证明可以直接扩展到针对相干攻击的情况。 在实际情况下的数值模拟显示，除了长通信距离外，该协议主动和被动实现之间的安全密钥速率差异可以忽略不计。 显示英文摘要

摘要： The Bennett-Brassard 1984 protocol (BB84 protocol) is one of the simplest protocols for implementing quantum key distribution (QKD). In the protocol, the sender and the receiver iteratively choose one of two complementary measurement bases. Regarding the basis choice by the receiver, a passive setup has been adopted in a number of its implementations including satellite QKD and time-bin encoding one. However, conventional theoretical techniques to prove the security of BB84 protocol are not applicable if the receiver chooses his measurement basis passively, rather than actively, with a biased probability, followed by the measurement with threshold detectors. Here we present a fully analytical security proof for such a decoy-state BB84 protocol with receiver's passive basis choice and measurement with threshold detectors. Thanks to the analytic nature, our security proof can straightforwardly be lifted up to the one over coherent attacks. The numerical simulations under practical situations show that the difference in secure key rate between the active and the passive implementations of the protocol is negligible except for long communication distances.