Experimental Investigation of Protection Method for Detection of Cloning Attack on Paper Certificates

A method of paper certificate protection against a cloning attack is investigated, that was proposed recently theoretically in a paper of the same author. This method is based on the use of digital watermarks. In order to extend watermark approach to a protection against cloning attacks, it has been suggested to execute estimation of the noise power which appear during the image scanning and printing. Algorithms of embedding and extraction of watermarks out of the images are presented along with a method of detecting of the cloning attack after scanning and printing by an attacker. Numerical results of the experiments for the error probabilities of a cloning missing and a false alarm are also presented and are in agreement with theoretical results obtained before.