A simple participant attack on the Bradler-Dusek protocol  (pp329-334)
          Fei Gao, Su-Juan Qin, Qiao-Yan Wen, and Fu-Chen Zhu  
          doi: https://doi.org/10.26421/QIC7.4-4
Abstracts: The ring-arrangement quantum secret sharing protocol in the paper [K. Br\'{a}dler and M. Du\v{s}ek (2004) {\textit{J. Opt. B: Quantum Semiclass. Opt.}} {\textbf{6}} 63] is analyzed and it is shown that this protocol is secure for any eavesdropper except for a dishonest participant. For example, by a special strategy, Bob can steal Charlie's portion of information without being detected and then recover Alice's secret by himself. We give a description of this strategy and point out a possible way to improve the protocol to stand against this attack.
Key words:  secret sharing, quantum cryptography, cryptanalysis, Br�adler-Duˇsek protocol