Hierarchical multiple image watermarking for image authentication and ownership verification

We propose a novel scheme in which two black and white images are embedded as watermarks into a host image. The first watermark is intended for secure image authentication and the second one is to verify the ownership. The two watermarks are embedded into the least significant bits of the host image using a private secret key in such a way that these images remain perceptually invisible to human eyes. The multiple watermark images can be easily extracted at the receiver site blindly, i.e., without aid of the original host image. If the watermarked image is tampered in any way, the recipient can only extract the first watermark image and the region of tampering will appear on it, whereas the second extracted watermark image will reveal only a random noisy image.