LAUSR

This paper presents a new and comparatively secure watermarking technique, in the frequency domain. Our scheme deploys a local ring-based substitution box (S-box). The algebraic algorithm used to synthesize S-box basically exploits one–one correspondence between the multiplicative group of units of the local ring $${\mathbb{Z}}_{512}$$Z512 and the Galois field $$\varvec{F}_{256}$$F256. This S-box has high confusion creating capability due to the structural properties of the local ring and fulfills the necessary requirements to be reliably used in multimedia applications. We use this S-box in a watermarking scheme to make our technique more confusing and secure to provide more support in copyrights protection strategies. The proposed non-blind digital watermarking technique deals with the application of discrete cosine transform (DCT) in the frequency domain which is comparatively more robust than spatial domain techniques. In the proposed scheme, first the watermark image is substituted through the S-box, and the scrambled watermark is then embedded in the DCT-transformed host image.‘ To measure the strength of the proposed technique, simulation results and statistical analyses are made. Most significant analyses techniques including measures of homogeneity, contrast, energy, entropy, correlation, mean squared error and peak signal to noise ratio are applied which show coherent results. To determine the robustness of our is effectively strong.