Quantum key distribution (QKD) protocols aim at allowing two parties to generate a secret shared key. While many QKD protocols have been proven unconditionally secure in theory, practical security analyses of experimental QKD implementations typically do not take into account all possible loopholes, and practical devices are still not fully characterized for obtaining tight and realistic key rates. We present a simple method of computing secure key rates for any practical implementation of discrete-variable QKD (which can also apply to measurement-device-independent QKD), initially in the single-qubit lossless regime, and we rigorously prove its unconditional security against any possible attack. We hope our method becomes one of the standard tools used for analysing, benchmarking, and standardizing all practical realizations of QKD.

翻译：量子密钥分发协议旨在让通信双方生成共享密钥。尽管众多QKD协议在理论上已被证明具有无条件安全性，但实验QKD系统的实用安全性分析通常未能全面考虑所有潜在漏洞，且实际设备特性尚未得到充分表征以获取严格而实际的密钥率。我们提出了一种适用于任何离散变量QKD实际实现的密钥率计算方法（同样适用于测量设备无关QKD），首先在单比特无损耗体制下展开研究，并严格证明了其可抵御任意攻击的无条件安全性。我们期望该方法能成为分析、基准测试和标准化所有实际QKD实现的标准工具之一。