High-capacity (2,3) threshold quantum secret sharing based on asymmetric quantum lossy channels

The main weakness of entanglement is its sensitiveness to the photon loss. In this paper, we exploit the different transmission losses of the free-space and optical fiber quantum channels, to develop a novel approach for (2,3) threshold quantum secret sharing (QSS) of classical information. To be exact, the Dealer Alice allocates W-state to three participants Bob, Charlie and David in terms of the asymmetric losses of their quantum channels, preventing any one participant from recovering the secret alone, but allowing any two of them to recover the secret. In such a way, Alice can flexibly choose the suitable degree of freedom to allocate the quantum shares with respect to the loss characteristics of different quantum channels. Our proposed scheme improves the information capacity from three bits to (log ₂m+ 2) bits, where m denotes the dimension of orbital angular momentum, and improves the security and flexibility of quantum communication, confirming QSS as a realistic technology for safeguarding secret shares in transmission. This work opens a convenient and favorable way to perform QSS.