A Semi-Fragile Reversible Watermarking for 2D CAD Engineering Graphics with Accurate Tampering Localization

Abstract

A semi-fragile reversible watermarking algorithm for 2D CAD engineering graphics with accurate tampering localization is proposed. Firstly, all vertices in the 2D CAD engineering graphics are extracted and partitioned into groups. After that, the relative distance of these vertices are calculated, and the assigned group number is used as watermark. Finally, the watermark is embedded into the factor of relative distance by using an improved difference expansion. Experimental results and analysis show that the proposed algorithm can obtain a large capacity, good invisibility, and robust against translation, rotation, and uniform scaling. At the same time, it can detect malicious attacks such as entity modification, addition and deletion, and can locate the tampering areas with a high precision. As for the watermarked 2D CAD engineering graphics passing authentication, the original 2D CAD engineering graphics can be completely recovered. It has great potential in the application of integrity protection and content authentication of 2D CAD engineering graphics.