Visual cryptography using image pixel transparency with cover image

Transparency of pixels of the shares (the two or more encrypted images) can be used to reveal the secret image. The pixels of shares can be generated randomly or the cover image can be used to generate the first share. The encrypted shares generated using cover image seem to be visually less similar to those generated without using cover image. Also, on the basis of image similarity between shares and original image, further encryption of encrypted shares can be performed. Comparison of the outcomes when cover image is used and when not used to generate shares, shows that the latter is more sensitive to the transparency factor (alpha) than the former encouraging the use of properly selected cover image for visual cryptography using pixel transparency.