An experimental Quantum Key Distribution (QKD) implementation requires advanced costly hardware, unavailable in most research environments, making protocol testing and performance evaluation complicated. Historically, this has been a major motivation for the development of QKD simulation frameworks, to allow researchers to obtain insight before proceeding into practical implementations. Several simulators have been introduced over the recent years. However, only four are publicly available, only one of which models equipment imperfections. Currently, no open-source simulator includes all following capabilities: channel attenuation modelling, equipment imperfections and effect on key rates, estimation of elapsed time during quantum channel processes, use of truly random binary sequences for qubits and measurement bases, shared-bit fraction customization. In this paper, we present NuQKD, an open-source modular, intuitive simulator, featuring all the above capabilities. NuQKD establishes communication between two computer terminals, accepts custom inputs (iterations, raw key size, interception rate etc.) and evaluates the sifted key length, Quantum Bit Error Rate (QBER), elapsed communication time and more). NuQKD capabilities include optical fiber and free-space simulation, modeling of equipment/channel imperfections, bitstrings from True Random Number Generator, modular design and automated evaluation of performance metrics. We expect NuQKD to enable convenient and accurate representation of actual experimental conditions.

翻译：实验性量子密钥分发（QKD）的实现需要先进且昂贵的硬件，这在大多数研究环境中难以获取，导致协议测试与性能评估复杂化。历史上，这成为开发QKD仿真框架的主要驱动力，旨在让研究人员在实际实现前先获得洞察。近年来已有多种仿真器被提出，但仅有四种可公开获取，其中仅有一种能模拟设备缺陷。目前，尚无开源仿真器具备以下全部功能：信道衰减建模、设备缺陷及其对密钥速率的影响、量子信道处理过程耗时估算、使用真随机二进制序列生成量子比特与测量基、以及共享比特比例定制。本文提出NuQKD——一个开源、模块化且直观的仿真器，具备上述所有能力。NuQKD可建立两个计算机终端间的通信，接受自定义输入（迭代次数、原始密钥大小、截取率等），并评估筛选密钥长度、量子比特误码率（QBER）、通信耗时等指标。其功能涵盖光纤与自由空间仿真、设备/信道缺陷建模、基于真随机数生成器的比特串生成、模块化设计以及性能指标的自动化评估。我们预期NuQKD能够便捷且准确地表征实际实验条件。