An efficient and verifiable quantum secret sharing scheme based on a novel seven-qubit entangled state

Quantum secret sharing (QSS) harnesses quantum entanglement to securely distribute information among multiple parties, overcoming the vulnerabilities of classical secret sharing schemes, which rely on computational complexity and are susceptible to quantum computing threats. Existing multi-party QSS protocols often exhibit declining efficiency as the number of participants N increases, limiting the scalability. This paper proposes two efficient and verifiable QSS protocols based on a seven-qubit entangled (SQE) state. The first protocol can be extended to multi-party sharing, achieving a sharing efficiency of \(3/(2N+2)\)—a significant improvement over prior schemes. By retaining three particles and distributing the remaining four particles to participants in groups, the protocol enables the reconstruction of three classical secret bits per SQE state, resulting in a particle utilization rate of 75%. Security is ensured through random number generation, local unitary operations, and decoy state technology, which effectively defends against external eavesdropping and internal cheating. Scalable to \((N \ge 3)\) participants, this protocol reduces the secure multi-party quantum communication cost. The second protocol introduces the random dynamic distribution of particle pairs in three-party secret sharing. Compared to the first protocol, this approach simplifies the verification lists. Moreover, the use of random dynamic particle pair distribution enhances the security of the second protocol.