New constructions of the lattice-based visual secret sharing scheme using mixture of colors

In this paper, we treat visual secret sharing scheme (VSSS) for color images. We first evaluate the brightness of the decrypted color image under certain conditions on the mixture of colors. We obtain a general formula for the construction of VSSS using mixture of colors. We second propose an iterative algorithm for constructing VSSS in a practical situation. If we use the iterative construction, we have only to solve partial differential equations with small n even if n is actually large, where n denotes the number of participants. This iterative construction has never discussed in the both cases under the original images are black-white images and color images. Finally, we propose the way to embed a color image on each share for the case that the original image is color.