We give an example of a wide class of problems for which quantum-information protocols based on multisystem 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 multipartite 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 scalability and can be realized with state-of-the-art technology.

• Received 22 January 2015
• Revised 27 March 2015

DOI:https://doi.org/10.1103/PhysRevA.92.030302