Alternatives to visual cryptography for colored images

This paper presents three simple methods alternatives to visual cryptography for colored images. In the first method, an RGB colored image is converted to HSI image generating 8 sub-images. Then each sub-image is divided to an arbitrary number of slides (8 slides) sub-images and encrypted using XOR operation with HSI random keys. A substitution process is applied for decryption followed by HIS/RGB conversion. With the second method and after RGB/HIS conversion, a bit by bit is taken from the original image and inserted them in each key image (8 images). The third method converts the original image and the key image into 3 sub-images (R,G,B) and takes a bit by bit for each pixel from the red, green, blue bands and insert them in the LSB in each of the key image (8 images). Finally the results of the three methods are compared.