Proposing Progressive Visual Cryptography Scheme for Color Images by Halftone Technique

Abstract

In visual cryptography, a secret picture is encoded into n bits of noise, similar to sharing, and this is a significant data encoding method. The hidden picture can be decrypted by the naked eye if there are more than k shares stacked out of n shares; this cannot be done if there are less than k shares accessible. Using the halftoning approach, a novel progressive visual cryptography (PVC) scheme for colour pictures is proposed in this study. A chromatic picture is first reduced to three monochromatic images in red, blue, and green tones. This is the first step. The halftone approach is used to convert these three pictures into binary images. It is the unexpanded VC method that reveals the secret image sharing in binary pictures.