Improved dynamic multiparty quantum direct secret sharing protocol based on generalized GHZ states to prevent collusion attack

Abstract

In 2018, Song et al. [Quantum Inf. Process 17, 244 (2018)] proposed a dynamic quantum direct secret sharing (DQDSS) protocol based on generalized GHZ states. However, this protocol is vulnerable to a security problem, known as the collusion attack, using which the dishonest agents can collude to reveal the master key without collaborating with other agents. This security problem, if unaddressed, can prevent the protocol from providing the secret sharing function. Therefore, this study proposes an improved DQDSS protocol to address the security problem in Song et al.’s DQDSS protocol. The proposed DQDSS protocol is resistant to the collusion attack and various other common attacks. Furthermore, the advantages of Song et al.’s DQDSS protocol are retained in the proposed scheme.