Content based image authentication with error correction

A watermarking scheme for content based image authentication is proposed which, in addition to authentication, has the ability to localize and correct modifications / errors. The watermark is based on the frequency domain features of an image and it is protected using error correcting codes. The use of error correcting codes helps in error localization and correction. The frequency domain features are additionally protected using an approximate message authentication code. This provides tolerance in image authentication when some of the image data cannot be reconstructed due to transmission errors or by legitimate image processing operations such as quantization, compression etc. The minor variations in the image data might not change the content of the image and therefore by correcting some errors, and being tolerant to the errors below a pre defined threshold, results in successful content authentication. Simulation results support that some unintentional data modifications, such as those due to minor channel noise, can be localized and corrected resulting in successful content authentication. Additionally, the simulation results for intentional modifications show the error localization and forgery detection capability of the proposed algorithm.