A copyright protection scheme for digital images using visual cryptography technique

A robust copyright protection scheme for digital image is proposed in the paper. In the proposed scheme, the watermark does not require to be embedded into the protected image but is used to generate a secret image and a public image by using the visual cryptography technique. Then the secret image is registered to certified authority (CA) for further protection. In the step of watermark extraction, the watermark can be acquired by performing exclusive-OR (XOR) operation between the secret image and the public image. The experimental results show that the proposed scheme not only can clearly verify the copyright of the digital image, but also is robust to withstand several image processing attacks such as JPEG lossy compression, cropping, noise adding, sharpening and blurring attacks.