  In this paper we introduce a quantum information theoretical model for
quantum secret sharing schemes. We show that quantum information theory
provides a unifying framework for the study of these schemes. We prove that the
information theoretical requirements for a class of quantum secret sharing
schemes reduce to only one requirement (the recoverability condition) as a
consequence of the no-cloning principle. We give also a shorter proof of the
fact that the size of the shares in a quantum secret sharing scheme must be at
least as large as the secret itself.
