Remote information concentration by GHZ state and by bound entangled   state
  We compare remote information concentration by a maximally entangled GHZ state with by an unlockable bound entangled state. We find that the bound entangled state is as useful as the GHZ state, even do better than the GHZ state in the context of communication security. 
Yafei Yu, Xiaoqing Zhou, Jian Feng and Mingsheng Zhan