Random grid-based visual secret sharing with multiple decryptions

Visual cryptographic scheme (VCS) with multiple decryptions has the features of both OR-based VCS (OVCS) and XOR-based VCS (XVCS), which can be applied in wider applications. In this paper, a threshold VCS with the abilities of OR and XOR decryptions is proposed based on random grids (RG). If a copy machine is not available, the secret could be reconstructed by stacking. On the other hand, if a device having XOR operation is available, the visual quality of the recovered secret image is improved as well as the secret can be reconstructed losslessly for (k,n) threshold (case) when n shares are collected. Experiments are conducted to evaluate the security and efficiency of the proposed scheme.