Spatial and Frequency Domain Complementary Watermarks for Image Authentication and Correction

A dual watermarking scheme for content based image authentication as well as error location and correction is proposed. One of the watermarks is based on image features in the spatial domain and the other one is based on image features in the frequency domain. Both of the watermarks complement each other. A tolerance to modifications, below a threshold, is obtained by protecting the spatial domain edge features using approximate message authentication codes, which are able to tolerate minor modifications. By protecting the frequency domain transform coefficients with error correcting codes, errors or modifications are located and corrected if possible. Simulation results in the presence of unintentional modifications, such as channel noise, show the noise tolerant authentication capability. Simulation results for intentional modifications show error localization and correction capability against forgery attacks. Security analysis is given at the end to analyze the security strength of the proposed image authentication scheme.