Visual Cryptography for Color Image with Discrete Wavelet Transform & Chaos Theory

Abstract

Visual Cryptography is usually a special type of cryptographic scheme where the decryption of encrypted message is conducted by the human visual system with simple computation dislike some kinds of cryptography that depend on complex mathematical calculations but with the developments in this day there is need to increase the complexity and the introduction of mathematics to prevent breaking algorithm. Visual Cryptography refers to any secrets for instance images or printed text. These kind of secrets are given into the system in the digital (image) form. The particular digital type of secrets is usually and then separated into different parts based on the pixel of the digital secret. These parts are referred to as shares. Visual cryptography was suggested in 1994 year by means of Naor and also Shamir who unveiled a fairly easy but completely safeguarded method that permits solution giving without complex cryptographic computation that they called as visual cryptography system (VCS). The shares are then overlapped the right way in order to visualize the secret. This proposal shows how to use the discrete wavelet transform to create multiple shares and using the properties of chaos theory by using H´enon map where The H´enon map is one of the simplest two-dimensional mappings exhibiting chaotic behavior then exchange image's pixels value among shares depend on this map , in the purpose of giving more security to shares and making break this algorithm more complex , shares must be create from plain image in the encryption algorithm then must collecting all shares to retrieve the original image in decryption algorithm .