摘要
与二维量子密钥分发相比,高维量子密钥分发(High-Dimensional Quantum Key Distribution,HD-QKD)能够提供更高的密钥率并且可以容忍更多的噪声.然而,在量子通信中,对高维量子系统的操作限制了其实用性.文章基于时间仓复用提出了一种HD-QKD协议.首先,使用高维编码的单光子在通信双方的多对二维量子存储器(Quantum Memory,QM)之间创建可预报的并行纠缠;然后,通过对多对QM进行贝尔态测量,两个通信方可以检测窃听并获取密钥,无需额外的测量来检验安全性,这使得HD-QKD协议在成本和效率上都具有优势.此外,文章获得了实现最优密钥容量的条件,并讨论了HD-QKD协议的两个重要的密码学应用,即确定性安全的量子通信和量子保密查询.与现有方法相比,两者在效率上都有显著提高.综上所述,时间仓复用方法在解决密码学问题中具有强大能力.
Abstract
High-dimensional quantum key distribution(HD-QKD)can provide higher secret key rates and tolerate more noise than two-dimensional QKD.However,the manipulation of quantum systems of higher dimensions limits the practicality in quantum communications.This article presented an alternative protocol for HD-QKD based on time-bin multiplexing.Parallel entanglement was first created between multiple pairs of two-dimensional quantum memories(QMs)located as two communicating parties in a heralded way by means of single photons with high-dimensional encoding.Then by performing Bell state measurements on their QMs by twos,two communicating parties could detect eavesdropping and obtain the secret key.No alternative measurements were needed to check security.This made the present HD-QKD protocol cost-effective and efficient.Furthermore,this article obtained the condition that the optimal key capacity was achieved.This article also discussed two other important cryptographic applications based on the present HD-QKD protocol,deterministic secure quantum communication and quantum privacy query,where the significant increased in efficiency over the existing methods can be achieved.In summary,the time-bin multiplexing method has strong capabilities in solving cryptographic problems.
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