Visual cryptography is a technique that uses human visual system to decode the secret message, which can be text, number, symbol or image. It represents the secret message by several different binary images, and when parts or all of these binary images are aligned and stacked together, the secret message will be revealed by human visual system without using computers and any knowledge about cryptography. In this plan, we will propose a visual cryptograph scheme which is able to conceal the secret data double in size than that through the existing scheme. Moreover, we also propose two schemes for visual authentication based on this visual cryptograph scheme. These two schemes can also detect the alteration by human visual system if the received message is altered by an adversary.
- Moni Naor' s Visual Cryptography home page.
- Doug Stinson's Visual Cryptography Page.
- Colored Visual Cryptography.