A Short Survey on Visual Cryptography Schemes

Visual Cryptography Scheme (VCS) is an encryption method that uses combinatorial techniques to encode secret written materials. The idea is to convert the written material into an image and encode this image into n shadow images. The decoding only requires only selecting some subset of these n images, making transparencies of them, and stacking them on top of each other. In this survey paper, we will provide the readers an overview of the basic VCS constructions, as well as several extended work in the area. In addition, we also review several state-of-art applications that take full advantage of such simple yet secure scheme.