Quantum steering as a resource for secure tripartite Quantum State Sharing

TL;DR

This paper demonstrates that quantum steering is a crucial resource enabling secure tripartite quantum state sharing among untrusted players, optimizing resource use for sharing Gaussian states.

Contribution

It identifies quantum steering as the key resource for secure quantum state sharing with untrusted parties, providing analysis for Gaussian states.

Findings

Quantum steering enables secure sharing among untrusted players.

Optimal resource use for sharing Gaussian states.

Analysis of steering levels needed for security.

Abstract

Quantum State Sharing (QSS) is a protocol by which a (secret) quantum state may be securely split, shared between multiple potentially dishonest players, and reconstructed. Crucially the players are each assumed to be dishonest, and so QSS requires that only a collaborating authorised subset of players can access the original secret state; any dishonest unauthorised conspiracy cannot reconstruct it. We analyse a QSS protocol involving three untrusted players and demonstrate that quantum steering is the required resource which enables the protocol to proceed securely. We analyse the level of steering required to share any single-mode Gaussian secret which enables the states to be shared with the optimal use of resources.