| Watermarking is the process that embeds data called a watermark, a tag, or a label into a multimedia object, such as images, video, or text, for some purpose. There are two types of watermark, fragile watermark and robust watermark. A (semi-)fragile watermark is a mark which is (highly) sensitive to a modification. A fragile watermarking scheme should be able to detect any change in the signal and identify where it has taken place and possibly what the signal was before modification. It serves at proving the authenticity of a document.In a networked environment, multimedia authentication is an increasing important issue. Fragile digital watermark thus come into being, which works effectively for multimedia content authentication by embedding a watermark to multimedia documents without influencing the vision or hearing effect of multimedia. When the content of multimedia is suspected, the extraction of fragile watermark can be used to detect and localize tampers, even present the category of tampering. But there are still few people study on this topic, this paper is about the research on image authentication technique using fragile watermarkingThis paper gives a brief overview of fragile digital watermarking into the context of image authentication, then comes the discussion of current algorithms and VLSI implement. After the discussion, two effective fragile watermarking algorithms are proposed, one is a spatial domain based algorithms combines with Keyed-Hash Message Authentication Code, which has high security, and the other is a transform domain based methods, which can embedded into JPEG Encoder. Both of them are very suitable for the hardware implementation, which is fast and low-cost. |
