International Journal of Quantum Information
SECURITY OF MULTIPARTY QUANTUM SECRET SHARING WITH MULTIQUBIT GHZ STATES
Xin-Wen Wang, Deng-Yu Zhang, Shi-Qing Tang, Gao Feng
Abstract
We study the security of multiparty quantum secret sharing (QSS) with multiqubit Greenberger–Horne–Zeilinger states. We give a detailed proof that the original scheme of Xiao et al. [Phys. Rev. A69 (2004) 052307] is insecure against the interior attack (i.e. the participants' attack) which is the most serious threat for QSS protocols. Thereafter, an improvement of this QSS protocol is proposed.