Entanglement Split:Comment on ``Quantum secret sharing based on reusable   Greenberger-Horne-Zeilinger states as secure carriers'' [Phys. Rev. A 67,   044302 (2003)]
  In a recent paper [S. Bagherinezhad and V. Karimipour, Phys. Rev. A 67, 044302 (2003)], a quantum secret sharing protocol based on reusable GHZ states was proposed. However, in this comment, it is shown that this protocol is insecure because a cheater can gain all the secret bits before sharing, while introducing one data bit error at most in the whole communication, which makes the cheater avoid the detection by the communication parities. 
Jian-Zhong Du, Su-Juan Qin, Qiao-Yan Wen and Fu-Chen Zhu