Measurement‐Device‐Independent Continuous‐Variable Quantum Secret Sharing

Abstract Although continuous‐variable quantum secret sharing (CVQSS) is theoretically proven to be secure, it may still be subject to various practical attacks due to the imperfections of devices. In this study, measurement‐device‐independent CVQSS (MDI‐CVQSS) is proposed in which measurement is no longer the duty for the dealer but is performed by an untrusted party Charlie, so that all detector side‐channel attacks can be eliminated, greatly enhancing the practical security of CVQSS system. The security bound is derived for the proposed MDI‐CVQSS, and its numerical simulation shows that MDI‐CVQSS outperforms conventional CVQSS in terms of both secret key rate and maximal number of users. It is found that MDI‐CVQSS possesses several unique properties, such as local stability of the secret key rate, low total excess noise and high utilization rate of raw data, which indicate that MDI‐CVQSS has the potential for efficiently building a large‐scale quantum communication network. Moreover, it is also suggested three variations of MDI‐CVQSS to satisfy the requirements of different multi‐point quantum communication scenarios.