A new visual cryptography based watermarking scheme using DWT and SIFT for multiple cover images

In this paper, a new Visual Cryptography based watermarking scheme for multiple cover images is proposed. The proposed scheme conceals watermark without altering the original cover images. First, it extracts the feature shares by applying the discrete wavelet transform (DWT), Singular value decomposition (SVD), and scale invariant feature transform (SIFT) on the cover images. The extracted feature shares are then used together with the private key and watermark to construct a secret share. The secret share should be registered with a trust authority. When a dispute over cover images happens, watermark can be extracted by using private key, feature shares, and secret share. The experimental results showed the method robustness versus various attacks, especially rotation and scaling.