A diffusion pattern composed of two-dimensional diffusion dots for encrypting a digital image

Abstract

Diffusion patterns composed of two-dimensional (2D) diffusion dots can show dynamic images by changing their illuminating or viewing conditions. In this study, a binary-exposure method is applied to the diffusion dots of a diffusion pattern to encode binary data into the diffusion pattern. Then the diffusion pattern not only can show a dynamic image but can also encrypt a covert digital image. The reconstructed covert image decoded from the diffusion pattern is exactly the same as the original covert image. Encoding a covert image into a diffusion pattern with 2D diffusion dots is very easy for a manufacturer, but decoding the covert image from the diffusion pattern is very difficult for counterfeiters. Therefore, the proposed encrypting scheme possesses both feasible and confidential features.