Cryptanalysis and improvement of dynamic quantum secret sharing protocol based on two-particle transform of Bell states

摘要

Recently, Du and Bao proposed a quantum secret sharing protocol based on two-particle transform of Bell states. We study the security of the proposed protocol and find that it is not secure, that is, the two dishonest agents, Bob and Zach, can collude to obtain Alice's secret messages without the help of the other agents. Finally, we give a possible improvement of the proposed protocol.