Quantum networks comprised of entangled end nodes serve stronger than the classical correlation for unparalleled quantum internet applications. However, practical quantum networking is affected by noise, which at its worst, causes end nodes to be described by pre-existing classical data. In such untrusted networks, determining quantum network fidelity and genuine multi-node entanglement becomes crucial. Here, we show that determining quantum network fidelity and genuine N-node entanglement in an untrusted star network requires only N + 1 measurement settings. This method establishes a semi-trusted framework, allowing some nodes to relax their assumptions. Our network determination method is enabled by detecting genuine N-node Einstein-Podolsky-Rosen steerability. Experimentally, using spontaneous parametric down-conversion entanglement sources, we demonstrate the determinations of genuine 3-photon and 4-photon quantum networks and the false positives of the widely used entanglement witness, the fidelity criterion of 1/2. Our results provide a scalable method for the determination of multipartite entanglement in realistic quantum networks.

由纠缠终端节点组成的量子网络比经典相关性更强，可用于无与伦比的量子互联网应用。然而，实际的量子网络会受到噪声的影响，在最坏的情况下，会导致终端节点由预先存在的经典数据来描述。在这种不可信的网络中，确定量子网络的保真度和真正的多节点纠缠变得至关重要。在这里，我们表明，确定不可信星形网络中的量子网络保真度和真正的N节点纠缠仅需要N + 1 个测量设置。这种方法建立了一个半信任的框架，允许一些节点放松他们的假设。我们的网络确定方法是通过检测真正的N节点 Einstein-Podolsky-Rosen 可操纵性来启用的。在实验上，我们使用自发参数下转换纠缠源，演示了真正的 3 光子和 4 光子量子网络的确定以及广泛使用的纠缠见证的误报，即 1/2 的保真度标准。我们的结果为确定现实量子网络中的多部分纠缠提供了一种可扩展的方法。