Security Enhancement for Color Images via Invisible Watermarking and Reversible Data Hiding in Encrypted Domain

In this paper we propose a security enhancement method for color images management. Our proposed algorithm is a combination of invisible watermarking and reversible data-hiding, both performed in the encrypted domain of the color images. Initially, the original image is converted from RGB to YCbCr color model and then each component is ciphered by applying a chaotic mixing procedure by using a first content owner's key. Reversible data hiding technique is used to embed additional bits into the ciphered chrominance information. With purposes of ownership authentication, an invisible watermarking technique is used to embed a watermark into the ciphered luminance information. Finally, to increase the security of the method, the ciphered chrominance and luminance components with hidden data are ciphered again by using a second content owner's key and a lightweight encryption algorithm. Three options are available for receivers who hold different keys: a) extract embedded additional bits and the watermark, b) decrypt the watermarked image with embedded additional bits, or c) extract the additional bits, the watermark and generate the recovered image that is identical to the original, respectively. Experimental results show the imperceptibility, capacity and security of the proposed method in the context of watermarking and reversible data hiding techniques, respectively.