Untrusted node networks initially implemented by measurement-device-independent quantum key distribution (MDI-QKD) protocol are a crucial step on the roadmap of the quantum Internet. Considering extensive QKD implementations of trusted node networks, a workable upgrading tactic of existing networks toward MDI networks needs to be explicit. Here, referring to the nonstandalone (NSA) network of 5G, we propose an NSA-MDI scheme as an evolutionary selection for existing phase-encoding BB84 networks. Our solution can upgrade the BB84 networks and terminals that employ various phase-encoding schemes to immediately support MDI without hardware changes. This cost-effective upgrade effectively promotes the deployment of MDI networks as a step of untrusted node networks while taking full advantage of existing networks. In addition, the diversified demands on security and bandwidth are satisfied, and network survivability is improved.

中文翻译：

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非独立网络的独立于测量设备的量子密钥分发

最初由独立于测量设备的量子密钥分发（MDI-QKD）协议实现的不可信节点网络是量子互联网路线图上的关键一步。考虑到可信节点网络的广泛 QKD 实现，需要明确现有网络向 MDI 网络的可行升级策略。在这里，参考 5G 的非独立 (NSA) 网络，我们提出了 NSA-MDI 方案作为现有相位编码 BB84 网络的演进选择。我们的解决方案可以升级采用各种相位编码方案的 BB84 网络和终端，以立即支持 MDI，而无需更改硬件。这种高性价比的升级有效地促进了MDI网络作为不可信节点网络的一步部署，同时充分利用了现有网络。此外，