Hybrid watermarking based on chaos and histogram modification

A hybrid watermarking scheme for authentication is presented, which demonstrates robustness against various attacks. Due to the different nature of filtering and geometrical attacks, two different watermarks are used in this scheme. The first one is embedded in frequency domain combined with a chaotic function and is based on the correlation method. The second watermark is embedded in luminosity histogram of the image. In this way, this hybrid watermarking scheme combines the robustness of chaotic domain against filtering, noise and compression attacks with the robustness of histogram domain against geometrical attacks.