Abstract: Quantum secret sharing (QSS) is an important branch of quantum cryptography, which can transmit the secret keys between the untrusted users. In this research, a novel QSS scheme with a trustful center is proposed, which the qubit generating devices and the qubit measuring devices are only equipped at the center. The center can provide the users with quantum states and measure quantum states from the users. The users only perform unitary operations and exchange operations to transmit the secret keys and to prevent eavesdropping. Simultaneously, the cooperative operations must be performed between Bob and Charlie to obtain the secret keys. The theoretical analysis shows that the scheme is immune to the conventional attacks in QSS, such as, the intercept-and-resend attack, the entangle-and-measure attack and the correlation-elicitation attack, etc. As the numbers of qubit generating and measuring devices are reduced greatly, the scheme provides a practical way for QSS technique with less cost.

Key words: quantum optics; quantum secret sharing (QSS); a trustful center; Bell states；exchange operations