Improvement of a multi-layer quantum secret sharing based on GHZ state and Bell measurement

Recently, a novel Multi-layer Quantum Secret Sharing (MQSS) scheme based on GHZ state and generalized Bell measurement is presented in [X.-J. Wang, L.-X. An, X.-T. Yu and Z.-C. Zhang, Phys. Lett. A 381(38) (2017) 3282.]. The novelty of the MQSS scheme is that a quantum secret can be shared by up to 3n parties at the nth layer. In this paper, we show that the MQSS scheme can be significantly simplified and improved. The improved MQSS scheme is much easier to implement in practice and more efficient. In our improved scheme, the parties of the nth layer need not put their particles together to carry out the generalized Bell measurement, which is needed to share the secret to the next layer in the original scheme. Instead, each party only has to carry out local operations.