Enhanced multiparty quantum secret sharing of classical messages by using entanglement swapping

Based on the multiparty quantum secret sharing (QSS) protocol called Zhang-Man protocol, the authors proposed two schemes to enhance the transmission efficiency of whole protocol. In the proposed improved protocol, the dealer can transmit double amount of secret messages at a time securely instead of doing the original Zhang-Man protocol twice. Besides, the authors save a lot of cost of whole QSS system. When the amount of secret messages is large and the number of agents is more, the performance of our protocol is much better than the Zhang-Man protocol. The authors also proposed a reuse scheme, after the secret message had been deduced, the left qubits can be reused for a new round. All of the scheme the authors mentioned above could be extended to multiparty cases in practice.