Dynamic quantum secret sharing based on graph states with agent management in pre-measurement and post-measurement phases

This paper proposes an advanced dynamic quantum secret sharing (DQSS) protocol that leverages the graphical properties of graph states. Unlike most existing DQSS protocols, the proposed scheme supports the dynamic addition and revocation of agents both before and after measurements are performed. In the pre-measurement phase, the dealer can adjust agent participation through graphical operations without requiring any action from the agents. In the post-measurement phase, two approaches are introduced to address different security requirements. In the first approach, agents’ shadow keys are hidden from the dealer, which enhances security but requires agent cooperation and incurs additional cost. In the second approach, the shadow keys are revealed to the dealer, which simplifies revocation without additional cost. Moreover, the proposed protocol requires only single-qubit measurements from agents. In terms of security, it resists collusion and attacks by dishonest revoked agents, and it relies solely on one-way quantum channels, thereby eliminating the need for additional devices to prevent Trojan horse attacks.