Off-line authentication using watermarks

Abstract

In this paper, we propose a new method for the secure and practical watermarking system. This method is designed to use printed images in the off-line authentication, where one determines whether a printed image has been altered intentionally since the first printing time, perhaps by a malicious party. This system is based on the fragile watermarking technologies to detect the transforms such as PS(printing and scanning) distortions, slight rotations and croppings, etc. With the human visual system, this watermarking system can detect the watermark in a image with random noises and can be applied for the practical use.