Efficient Mediated Multiparty Semi-Quantum Secret Sharing Protocol Based on Single-Qubit Reordering

Abstract

Typical multiparty semi-quantum secret sharing (MSQSS) protocols require the dealer to possess full quantum capabilities, while the classical users usually need to perform three operations. To address this practical limitation, this paper introduces a new mediated MSQSS protocol that enables Alice, a classical user, to share a secret with $M$ classical Bobs, with the assistance of an untrusted third party (TP) who may attempt any possible attack to steal Alice's secret. Furthermore, the classical participants require only two capabilities instead of three, namely: (a) performing measurements in the $Z$ basis; and (b) reordering qubits. The proposed scheme offers significant advantages over existing mediated QSS protocols: (1) it is the first mediated SQSS protocol to adopt single qubits, instead of entangled states, as the quantum resource, which makes it more practical and easier to implement; (2) It achieves higher qubit efficiency. Security analysis also demonstrates that the protocol is secure against well-known attacks.