具有掩盖图像的(2,2)可视密码方案

(2,2)Visual Cryptography Schemes With Covert Image

为解决传统可视密码像素膨胀及分存图像无意义等问题,文中提出了一个具有掩盖图像的(2,2)可视密码方案。方案中密图为黑白反色图像,利用半色调技术将两个灰度图像处理后的半色调图像作为掩盖图像,根据密图修改掩盖图像生成分存图像,叠加分存图像恢复密图。方案符合可视密码解密简单的特性且分存图像有意义,没有引入任何像素膨胀。

Conventional Visual Cryptography Scheme suffers from complicated construction method, pixel expansion and meaningless share images. To solve these problems, a （2, 2） VCS with Covert Image based halftoning is proposed. In this scheme, the concealed secret image is the special black white image with black background while the secret message on it is white. Halftoning is used to convert two grey covert images into two halftone covert images. Two share images could be attained by modifying the halftone covert images in accordance with the secret image. By stacking the two share images the secret image is revealed. Experiments indicate that the proposed scheme absolutely accords with the feature of easy decoding for VCS. Furthermore, the construction method of the proposed scheme is relatively simple, the achieved shares are meaningful and without any pixel expansion.