A New Secret Coloured Image Encryption and Decryption Scheme based on (2, 2) Visual Cryptography Scheme (VCS)

Cryptography is an art and science of achieving security by en-coding the message to make them non-readable. Extended Visual Cryptography is a type of cryptography which encodes a number of images in the way that when the images on transparencies are stacked together, the hidden message appears without a trace of original images. The decryption is done directly by the human visual system(HVS) with no special cryptographic calculations. We present a system which takes three pictures as an input and generates two images which correspond to two of the three input pictures. The third picture is reconstructed by printing the two output images onto transparencies and stacking them together. Generally, visual cryptography suffers from the deterioration of the image quality. This paper also describes the method to improve the quality of the output images.