Quantum key distribution (QKD) is a proven secured way to transmit shared secret keys using quantum particles. Any adversarial attempt to intercept and eavesdrop secret key results in generating errors alerting the legitimate users. Since QKD is constrained by quantum mechanics principles, the practical transmission of the key at a greater distance is an issue. In this paper, we discover and analyze the key factors associated with transmission media, hardware components and protocol implementation of the QKD system that causes hindrance in distance range. Practical implementation of BB84 and KMB09 protocols is discussed to determine the achievable distance given current technology. We find that by using ultra low loss fiber, short-pulse laser and superconducting nanowire single photon detector the maximum achievable distance for both of the quantum protocols is 250[Formula: see text]km.

中文翻译：

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BB84和KMB09 QKD协议可实现距离分析

量子密钥分发 (QKD) 是一种经过验证的使用量子粒子传输共享密钥的安全方式。任何拦截和窃听密钥的对抗性尝试都会导致生成错误，警告合法用户。由于 QKD 受量子力学原理的限制，密钥在更远距离的实际传输是一个问题。在本文中，我们发现并分析了与 QKD 系统的传输介质、硬件组件和协议实现相关的导致距离范围障碍的关键因素。讨论了 BB84 和 KMB09 协议的实际实现，以确定在给定当前技术的情况下可实现的距离。我们发现通过使用超低损耗光纤，