A flexible multiple-secret image sharing scheme by shifting random grids

Visual secret sharing (VSS), also called visual cryptography (VC), which is widely used in consumer electronics (e.g., electronic voting and electronic lottery). Comparing with traditional cryptography, VSS combines traditional cryptography with conception of information sharing, and encoding a secret image into n pieces of share images. In 2012, a multiVSS scheme by shifting random grids has been proposed by Chang et al. In their proposed scheme, three secret images can be encrypted into two share images by using random grids. In addition, the distortion of each secret image is the same. In order to make the distortion more flexible, this paper propose a flexible multiple-secret image sharing scheme by shifting random grids. The advantage of the proposed scheme is that the distortion of the last secret image can flexibly be selected. So, the proposed scheme can be used more practical and flexible.