Quantum secret sharing in a triangular superconducting quantum network

Quantum networks enable secure communication, distributed computing, and precision sensing beyond classical capabilities. Recent advances have progressed from two-node links to multi-node architectures, enabling rigorous tests of multiparty quantum communication protocols. Among these, quantum secret sharing (QSS) leverages multipartite entanglement to distribute secrets such that only authorized parties can reconstruct them. Here, we present a three-node quantum communication testbed with a triangular topology, each edge implemented by a 1.3-meter-long transmission line, and use this testbed to demonstrate QSS. We demonstrate state transfer and entanglement generation between all node pairs, create genuine tripartite GHZ entanglement, and implement QSS of classical information. Our experiments show that the QSS protocol detects eavesdropping in situ, ensuring secure secret distribution on a superconducting platform.