Securing of Coloured Images Using Visual Cryptography and Digital Enveloping

Visual Cryptography is a Cryptography scheme which is used to secure images. In this scheme the image to be sent to receiver via sender is divided into number of shares and then they are sent to the receiver. In Decryption processes, these shares of images are combined or stacked together to get an original image. The initial model developed was only for the binary images. Later the black and white images or 0-1 image was further studied for the Coloured Images that means for Red, Green, and Blue. For the RGB images various methods have been developed but in all these techniques the received image has degraded quality. In this paper we propose a new algorithm with implementation for coloured visual cryptography and making it more secured by applying Digital Enveloping technique on the shares of the image. Digital Enveloping is a technique in which shares, of the image to be sent, are distributed over various sample images to create what is known Enveloped images. At the receiver end, shares are retrieved from the enveloped images and combined to form original image without degrading the quality of image. The important feature of the Visual Cryptography is decryption process is done by human eyes not the computer less computational power is required.