Abstract: Watermarking techniques are primarily used for copyright protection. A simple and robust watermark-like digital authentication scheme is proposed. This work has two major merits. First, the watermark used in the proposed authentication scheme is the same type used in the original image, e.g. grey level images. Second the proposed scheme meets the requirements for watermarking techniques. lllegal users cannot perceive and break the watermark signed from the original image. Furthermore, the signed watermark is robust against attacks by many image altering algorithms, such as filtering, lossy compression, rotation and scaling. The proposed scheme is not only suitable for ordinary natural images, but also for cartoon graphics.
Because of the proliferation of the Internet, a huge amount of multimedia content is available over the network for any user to browse and download. Today, many traditional transactions are conducted over the Internet, and new business applications are employed such as reading web newspapers, magazines, network audio, online pay-perview, video on demand, online consulting, componentbased software, virtual shopping, etc. Therefore, security and copyright issues have become increasingly important. Many security problems can be overcome using cryptography, but until now, copyright protection in the digital world has been lacking