二诱骗态相位匹配量子密钥分发方案

Two-Decoy-State Phase Matching Quantum Key Distribution Method

相位匹配协议是最近被提出的一种能突破密钥容量的量子密钥分发协议,其安全性得到了理论和实践的证明。针对实际应用中光源的非理想性,基于弱相干态光源,提出了一种二诱骗态相位匹配量子密钥分发方案。该方案在简化参量计算式的同时,仅采用2个诱骗态(真空+弱诱骗态)对求解最终密钥生成率的必要参数进行了估计;随后以光纤信道为背景,对该方案在理想及统计波动情况下的性能进行了仿真分析。仿真结果表明:在同等诱骗态数目条件下,二诱骗态相位匹配方案能突破密钥容量的限制,密钥生成效率及最大传输距离均优于BB84协议、测量设备无关协议等;在密钥生成效率及最大传输距离两个性能指标上,理想情况下二诱骗态方案接近已有的三诱骗态方案,但在考虑实际统计波动且数据量小于10^(14)时二诱骗态方案反而更优。

The phase matching protocol is a recent proposed quantum key distribution protocol that breaks the secret key capacity.Its security has been certified by theory and practice.For there is no ideal single photon source in practice,a two-decoy-states phase matching quantum key distribution method is proposed with a weak coherent state source.In this method,the parameters are estimated more easily for only two decoy states(vacuum+weak decoy state)should be taken into consideration that are necessary to solve the final key rate.Then we analyze the performance of the proposed method with fiber channel both in ideal and statistical fluctuation respectively.The simulation results show that the proposed method can break the secure key capacity and has higher key rate and longer max transmission distance than the BB84(the protocol proposed by Bennett and Brassard in 1984)and measurement device independent protocols under the condition of the same number of decoy state.The proposed method approaches the existing three-decoy-states method in key rate and max transmission distance and breaks the secret key capacity.Taking the statistical fluctuation into consideration,the proposed method will have higher key rate and longer max transmission distance when the data size is less than 10^(14).