Visual Cryptography Using Hybrid Halftoning

TL;DR: A survey has been done on various visual cryptography schemes based on the number of secret, pixel expansion, type of share generated, image format, and number ofsecret image.

TL;DR: A multi-scale image sharing scheme to hide multiple images to two meaningful sharing images that increases more capacity of hidden images than the conventional 2-out-of-2 visual cryptography does.

TL;DR: Wang et al. as discussed by the authors proposed a solution for digital image copyright protection technique using the combination of watermarking and visual encryption technique, where the copyright information (copyright logo) is distributed into n shares using the k-out-of-n-share distributed algorithm, also called (k, n) visual secret sharing method, one of the shares is randomly selected to embed into the original image to prove the user's copyright.

TL;DR: Experimental results of the proposed method compared with the method using only digital watermark show that the method has more practical effectiveness in the application of digital product copyright protection.

TL;DR: This paper examines graph-based access structures, i.e., access structures in which any qualified set of participants contains at least an edge of a given graph whose vertices represent the participants of the scheme, and provides a novel technique for realizing threshold visual cryptography schemes.

TL;DR: An extended visual cryptography scheme, for an access structure (ΓQual,ΓForb) on a set of n participants, is a technique to encode n images in such a way that when the authors stack together the transparencies associated to participants in any set X∈�Qual they get the secret message with no trace of the original images, but any X∈Γ forb has no information on the shared image.

TL;DR: The proposed method utilizes the void and cluster algorithm to encode a secret binary image into n halftone shares (images) carrying significant visual information, and shows that the visual quality of the obtained halftones are observably better than that attained by any available visual cryptography method known to date.

TL;DR: A (k, n)-threshold visual cryptography scheme is proposed to encode a secret image into n shadow images, where any k or more of them can visually recover the secret image, but any k - 1 or fewer of them gain no information about it.