Secret sharing of a quantum state

TL;DR

This paper demonstrates a quantum secret sharing scheme using six-photon entanglement, achieving high fidelity and ensuring confidentiality, while also sharing entangled quantum information and functioning as a quantum error-correcting code decoder.

Contribution

The authors experimentally implement a quantum threshold secret sharing scheme capable of sharing entangled quantum states with high fidelity, demonstrating confidentiality and error correction capabilities.

Findings

Shared quantum secrecy with 93% fidelity

Scheme ensures confidentiality with less than threshold players

Can share and recover entangled quantum information

Abstract

Secret sharing of a quantum state, or quantum secret sharing, in which a dealer wants to share certain amount of quantum information with a few players, has wide applications in quantum information. The critical criterion in a threshold secret sharing scheme is confidentiality, with less than the designated number of players, no information can be recovered. Furthermore, in a quantum scenario, one additional critical criterion exists, the capability of sharing entangled and unknown quantum information. Here by employing a six-photon entangled state, we demonstrate a quantum threshold scheme, where the shared quantum secrecy can be efficiently reconstructed with a state fidelity as high as 93%. By observing that any one or two parties cannot recover the secrecy, we show that our scheme meets the confidentiality criterion. Meanwhile, we also demonstrate that entangled quantum information can be shared and recovered via our setting, which demonstrates that our implemented scheme is fully quantum. Moreover, our experimental setup can be treated as a decoding circuit of the 5-qubit quantum error-correcting code with two erasure errors.