Li Yuanhao, Fei Yangyang, Wang Weilong, Meng Xiangdong, Wang Hong, Duan Qianheng, Han Yu, Ma Zhi
Opt Express. 2023 Jul 17;31(15):23813-23829. doi: 10.1364/OE.493586.
Heterodyne-based continuous-variable source-independent quantum random number generator (CV-SI-QRNG) can produce true random numbers without any assumptions on source. However, practical implementations always contain imperfections, which will greatly influence the extractable randomness and even open loopholes for eavesdroppers to steal information about the final output. In this work, based on the theoretical model, we systematically analyzed the effects of imperfect implementations on the practical security of heterodyne-based CV-SI-QRNG. The influences of local oscillator (LO) fluctuation under imbalanced heterodyne detection are first analyzed. The simulation results show that the lower bound of extractable randomness will be overestimated without considering the influence of LO fluctuation, which will threaten the practical security of CV-SI-QRNG system. Moreover, we analyze the effects of the degree of imbalance and the magnitude of LO fluctuation on evaluating the extractable randomness. Finally, we investigate the impact of an imperfect phase modulator on the practical security of CV-SI-QRNG and find it will reduce the extractable randomness. Our analysis reveals that one should carefully consider the imperfections in the actual implementations of CV-SI-QRNGs.
基于外差的连续变量源独立量子随机数发生器（CV-SI-QRNG）能够在不对源做任何假设的情况下产生真随机数。然而，实际实现总是存在缺陷，这将极大地影响可提取的随机性，甚至为窃听者窃取关于最终输出的信息打开漏洞。在这项工作中，基于理论模型，我们系统地分析了不完美实现对外差式CV-SI-QRNG实际安全性的影响。首先分析了不平衡外差检测下本地振荡器（LO）波动的影响。仿真结果表明，不考虑LO波动的影响会高估可提取随机性的下限，这将威胁CV-SI-QRNG系统的实际安全性。此外，我们分析了不平衡程度和LO波动幅度对评估可提取随机性的影响。最后，我们研究了不完美相位调制器对CV-SI-QRNG实际安全性的影响，发现它会降低可提取的随机性。我们的分析表明，在CV-SI-QRNG的实际实现中应仔细考虑这些缺陷。
