Analysis of efficient and secure dynamic quantum secret sharing protocol based on Bell states

Dynamic secret sharing can deal with the problems of both adding agents and revoking ones, which makes it more practical and flexible compared with general secret sharing. In this work, we analyze an efficient and secure dynamic quantum secret sharing protocol based on Bell states, and find that there is an unnoticed problem that it does not satisfy the requirement for dynamic secret sharing in the sense that if the access structure has been completed, then both adding an agent and revoking one become impossible by the way in this protocol; or else if adding an agent or revoking one can be realized, then the previous access structure has not been implemented in fact. Furthermore, we discuss how to solve this problem and give a possible way to improve this protocol.