Multibit Assignment Steganography in Palette Images

This letter proposes a novel multibit assignment steganography for palette images, in which each gregarious color that possesses close neighboring colors in the palette is exploited to represent several secret bits. A method for producing a usable multibit assignment is presented. For any pixel with a gregarious color, a data-hider can always find a suitable neighbor of the original color that corresponds to a prefix of secret bit-sequence and then replaces the original color with the found neighboring color. Experiment results show that the proposed steganography provides a good payload-distortion performance.