Palette Embedded Images by Steganographic Technique

Abstract: In this paper presents, a new steganographic technique for embedding messages in palette-based images, such as GIF files. Steganography is a method of secret communication wherein the very existence of communication is hidden. During the last few decades there has been a tremendous development in digital image steganography the new technique embeds one message bit into one pixel (its pointer to the palette). The pixels for message embedding are chosen randomly using a pseudo-random number generator seeded with a secret key. For each pixel at which one message bit is to be embedded, the palette is searched for closest colors. The closest color with the same parity as the message bit is then used instead original color. it has the advantage that both the overall change due to message embedding and the maximal change in colors of pixels is smaller than in methods that perturb the least significant bit of indices to a luminance-sorted palette, such as EZ Stego [1]. Indeed, numerical experiments indicate that the new technique introduces approximately four times less distortion to the carrier image than EZ Stego. The maximal color change is 4 to 5 times smaller for the new technique than that of EZ Stego. This method introduces less distortion to the carrier image will generally cause changes that are more difficult to detect, and will therefore provide more security.

Keywords: Steganography, Palette, Secret Communication, Luminance-Sorted Palette.