Hiding Multiple Watermarks in Transparencies of Visual Cryptography

This paper proposes a scheme to hide multiple watermarks in transparencies of visual cryptography. On one hand, the main properties of the traditional visual cryptography are still maintained. On the other hand, not only the encrypted image can be visible when stacking the transparencies, but also two extra watermarks can be extracted with simple computations. The scheme can be applied to hide some affiliated information of the secret image. Experimental results demonstrate the scheme is effective and practical.