  We give an example of a wide class of problems for which quantum information
protocols based on multi-system entanglement can be mapped into much simpler
ones involving one system. Secret sharing is a cryptographic primitive which
plays a central role in various secure multiparty computation tasks and
management of keys in cryptography. In secret sharing protocols, a classical
message is divided into shares given to recipient parties in such a way that
some number of parties need to collaborate in order to reconstruct the message.
Quantum protocols for the task commonly rely on multi-partite GHZ entanglement.
We present a multiparty secret sharing protocol which requires only sequential
communication of a single quantum d-level system (for any prime d). It has huge
advantages in scalabilility and can be realized with the state of the art
technology. n be realized with the state of the art technology.
