Comment on 'High-dimensional deterministic multiparty quantum secret sharing without unitary operations'

Recently, a high-dimensional deterministic multiparty quantum secret sharing (DMQSS) scheme was proposed (Liu ZH et al in Quantum Inf Process 1---11 2011). However, we show that the scheme is vulnerable to a specific kind of collusion attack. In the worst case, $${\left\lfloor n/2\right\rfloor+1}$$ agents can collude elaborately to reveal the dealer's secret without the help of the other agents. We present the attack strategy in details and also give two possible improvements to resist the proposed collision attack.