An image secret sharing scheme with the capability of previvewing the secret image

Some (k, n)-threshold image secret sharing schemes encrypt the secret image into n noise-like shadow images with size Ilk times that of the original secret image. The small size of shadow image makes this framework suitable for fast transmission in the distributed multimedia system where each shadow image is stored in the distributed storage node. However, noise-like shadow images are difficult to identify and manage. Accordingly, a so-called user-friendly scheme which shadow images show a shrunken version of the secret image was proposed to address the identification and management problems, but the portrait on shadow images had already leaked the secret information. Therefore, this user-friendly scheme is, strictly speaking, not a secret sharing scheme. In this paper, we introduce a new framework that the cost of verifying the validity of shadow images is mitigated by being able to simply superimpose shadow images to preview the image. Meantime the proposed scheme also provides noise-like shadow images to retain the secret sharing feature.