Wang Ke, Yang Xiu-Qing, Li Ting-Yu, Lin Ya-Qian, Hai Na, Yin Zhen-Qiang
Opt Express. 2023 Nov 20;31(24):40730-40740. doi: 10.1364/OE.506256.
Semi-quantum key distribution (SQKD) protocols are used to distribute secret keys between a quantum party and a classical party. However, existing SQKD protocols rely on two-way communication, and may still be vulnerable to Trojan horse side-channel attacks where Eve sends her own photon into a receiver's apparatus and measures the reflected photon to estimate the key. In this paper, we propose a practical SQKD with one-way key. This requires that the single photons travelling through the one-way channel are used to encode bit information, and the returned photons are used to quantify Eve's information, thus reducing the security analysis of the Trojan horse attack in SQKD. Meanwhile, our protocol with one basis enjoys security advantage in practical SQKD systems when source flaws are taken into account. In particular, the present protocol is secure under practical conditions when weak coherent pulses (WCP) are used. Our simulation results show that the protocol using WCP can distribute secret keys over a distance of 110 km without decoy states.
半量子密钥分发（SQKD）协议用于在量子方和经典方之间分发密钥。然而，现有的SQKD协议依赖双向通信，并且可能仍然容易受到特洛伊木马侧信道攻击，即伊芙将自己的光子发送到接收器设备中并测量反射光子以估计密钥。在本文中，我们提出了一种实用的单向密钥SQKD。这要求通过单向通道传播的单光子用于编码比特信息，而返回的光子用于量化伊芙的信息，从而降低了SQKD中特洛伊木马攻击的安全分析难度。同时，在考虑源缺陷的情况下，我们的单基协议在实际的SQKD系统中具有安全优势。特别是，当使用弱相干脉冲（WCP）时，本协议在实际条件下是安全的。我们的模拟结果表明，使用WCP的协议可以在不使用诱骗态的情况下在110公里的距离上分发密钥。
