For secure practical systems, quantum key distribution (QKD) must provide high key rates over long distances. Time-entanglement-based QKD promises to increase the secret key rate and distribution distances compared to other QKD implementations. This article describes the major steps in QKD protocols, focusing on the nascent QKD technology based on high-dimensional time-bin entangled photons. We overview state-of-the-art from the information and coding theory perspective. In particular, we discuss the key rate loss due to single-photon detector imperfections. We hope the open questions posed and discussed in this paper will inspire information and coding theorists to contribute to and impact fledgling quantum applications and influence future quantum communication systems.

翻译：为构建安全的实用系统，量子密钥分发（QKD）必须在长距离传输中实现高密钥速率。相比其他QKD实现方案，基于时间纠缠的QKD有望提升密钥生成速率与分发距离。本文阐述QKD协议中的关键步骤，重点聚焦于基于高维度时间箱纠缠光子的新兴QKD技术。我们从信息论与编码理论视角综述现有前沿成果，尤其探讨单光子探测器非理想性导致的密钥速率损失。希望本文提出与讨论的开放性问题能激发信息与编码理论研究者投身并影响新兴量子应用，进而塑造未来量子通信系统。