Efficient Multi-Party Quantum Secret Sharing Schemes
  In this work, we generalize the quantum secret sharing scheme of Hillary, Bu\v{z}ek and Berthiaume[Phys. Rev. A59, 1829(1999)] into arbitrary multi-parties. Explicit expressions for the shared secret bit is given. It is shown that in the Hillery-Bu\v{z}ek-Berthiaume quantum secret sharing scheme the secret information is shared in the parity of binary strings formed by the measured outcomes of the participants. In addition, we have increased the efficiency of the quantum secret sharing scheme by generalizing two techniques from quantum key distribution. The favored-measuring-basis Quantum secret sharing scheme is developed from the Lo-Chau-Ardehali technique[H. K. Lo, H. F. Chau and M. Ardehali, quant-ph/0011056] where all the participants choose their measuring-basis asymmetrically, and the measuring-basis-encrypted Quantum secret sharing scheme is developed from the Hwang-Koh-Han technique [W. Y. Hwang, I. G. Koh and Y. D. Han, Phys. Lett. A244, 489 (1998)] where all participants choose their measuring-basis according to a control key. Both schemes are asymptotically 100% in efficiency, hence nearly all the GHZ-states in a quantum secret sharing process are used to generate shared secret information. 
Li Xiao, Gui Lu Long, Fu-Guo Deng, Jian-Wei Pan