An asymmetric watermarking scheme based on visual cryptography

Digital watermarking is a very active research area for copyright protection of electronic documents and media. A visual cryptographic approach is used to generate two random shares of a watermark: one is embedded into the cover-image and another is kept as a secret key for the later watermark extraction. The watermark can be extracted by simply superimposing the key share over the stego-image. This asymmetric digital watermark is specially designed and is not easily changed or removed. But, it is very convenient to be extracted. The embedded digital watermark by this approach seems robust after several attacks are performed on the stego-image