  Inspired by Naor et al.'s visual secret sharing (VSS) scheme, a novel n out
of n quantum visual secret sharing (QVSS) scheme is proposed, which consists of
two phases: sharing process and recovering process. In the first process, the
color information of each pixel from the original secret image is encoded into
an n-qubit superposition state by using the strategy of quantum expansion
instead of classical pixel expansion, and then these n qubits are distributed
as shares to n participants, respectively. During the recovering process, all
participants cooperate to collect these n shares of each pixel together, then
perform the corresponding measurement on them, and execute the n-qubit XOR
operation to recover each pixel of the secret image. The proposed scheme has
the advantage of single-pixel parallel processing that is not available in the
existing analogous quantum schemes and perfectly solves the problem that in the
classic VSS schemes the recovered image has the loss in resolution. Moreover,
its experiment implementation with the IBM Q is conducted to demonstrate the
practical feasibility.
