A secret image sharing method based on block-wise cheating detection and recovery on shadow images

In (k, n) threshold schemes, it is very important to determine which shadow images are cheated on and which shadow images will be used in the recovery of the secret image. Also, some of the cheated shadow images may have not cheated regions. Therefore, authentication of the shadow image's blocks is necessary. In this paper, a secret image sharing method using block-wise cheating detection and recovery is proposed. With the proposed block-wise method, even if all shadow images have been cheated, recovery of the secret images is performed with the block-based authentication and recovery mechanism. In the proposed recovery process, it is sufficient for k of each paired block group in the n shadow image to be not cheated. Experimental results illustrated that the proposed method successfully recovered the secret image even if n shadow images were cheated, and the randomness of the proposed method is satisfactory.