Author : Sneha S. Walke and Vandana Navale

Many reversible data hiding schemes have been proposed and successfully applied in medical and military applications. These schemes are developed to ensure digital images authenticity and integrity without any distortion on the original images. The existing RDH techniques are designed for grayscale images and thus, cannot be directly applied to palette images. Since the pixel values in a palette image are not the actual color values, but rather the color indexes. Therefore RDH in the encrypted palette images is more challenging than that designed for the grayscale images. There is no suitable RDH scheme designed for encrypted palette images that has been reported, while palette images have been widely utilized. This has motivated us to design a reliable RDH scheme for encrypted palette images. The proposed method uses a color partitioning method to use the palette colors to construct a certain number of embeddable color-triples, their indexes are self-embedded into the encrypted image so that a data hider can collect the usable color-triples to embed the secret data. For a receiver, the embedded color-triples can be determined by verifying a self-embedded checkcode that enables the receiver to retrieve the embedded data only with the data hiding key. By using the encryption key, the receiver can roughly reconstruct the image content.

Keywords: Color Partitioning, Image encryption, Information hiding, Image recovery, Palette, Reversible data hiding,