Quantum Key Distribution (QKD) offers provably secure, information-theoretic key exchange, but in long-distance scenarios without quantum repeaters, Trusted Nodes (TNs) are commonly employed despite introducing critical security risks. We propose a redundant key management method for QKD network that combines Twin Field QKD (TF-QKD) (or Measurement-Device Independent (MDI)-QKD) with a novel key-routing scheme to eliminate the need for truly trusted TNs. Quantum measurements are handled entirely within the network, minimizing end-user hardware requirements. Multiple QKD links connect intermediate nodes such that a successful attack requires the collusion of multiple adversarial nodes, greatly enhancing security over the traditional TN model. In this contribution, we discuss the tradeoff between security, key rates, and distances supported by the new method. Our analysis reveals that the improved redundant key management system may enable true end-to-end connectivity over several thousand kilometers while maintaining high security standards.

翻译：量子密钥分发（QKD）可提供可证明安全的信息论密钥交换，但在无量子中继的长距离场景中，常采用可信节点（TN），而这会引入关键安全风险。我们提出一种用于QKD网络的冗余密钥管理方法，该方法将双场QKD（TF-QKD）（或测量设备无关（MDI）-QKD）与新型密钥路由方案相结合，以消除对真正可信节点的需求。量子测量完全在网络内部完成，最大限度降低终端用户硬件需求。多个QKD链路连接中间节点，使得成功攻击需要多个对抗节点协同合谋，相比传统TN模型极大增强了安全性。本文讨论新方法在安全性、密钥速率与支持距离之间的权衡。分析表明，改进的冗余密钥管理系统可在维持高标准安全性的同时，实现数千公里范围内的真正端到端连接。