Hard mathematical problems having no polynomial time algorithms to determine a solution are seemly in design of secure cryptosystems. The proposed watermarking system used number theoretic concepts of the hard higher order Diophantine equations for image content authentication scheme with three major phases such as 1) Formation of Diophantine equation; 2) Generation and embedding of dual Watermarks; and 3) Image content authentication and verification of integrity. Quality of the watermarked images, robustness to compression and security are bench-marked with two peer schemes which used dual watermarks.
This paper describes an authentication scheme that uses Diophantine equations based generation of the secret locations to embed the authentication and recovery watermark in the DWT sub-bands. The security lies in the difficulty of finding a solution to the Diophantine equation. The scheme uses the content invariant features of the image as a self-authenticating watermark and a quantized down sampled approximation of the original image as a recovery watermark for visual authentication, both embedded securely using secret locations generated from solution of the Diophantine equations formed from the PQ sequences. The scheme is mildly robust to Jpeg compression and highly robust to Jpeg2000 compression. The scheme also ensures highly imperceptible watermarked images as the spatio –frequency properties of DWT are utilized to embed the dual watermarks.
A semi fragile, public key based digital signature scheme to verify and authenticate digital images is proposed. The scheme computes a content dependent feature value for each block of DCT coefficients of the original image. This feature is signed and then embedded into the selected DCT coefficients of the image as watermark. The technique aims to circumvent the cut and paste attacks by incorporating inter block dependence during the watermarking procedure. The watermarked image demonstrated high perceptual quality and robustness. It also proved to be robust against many common image processing operations and JPEG compression. The scheme not only can verify the authenticity and the integrity of images, but also can locate the illegal modifications.
General TermsImage watermarking, authentication, content based watermarking
KeywordsInter block dependence, digital signature, content authentication, semi fragile watermarking, block wise percentage difference
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.