Fabien A. P. Petitcolas. Weakness of existing watermarking schemes. <http://www.cl.cam.ac.uk/~fapp2/ watermarking/image_watermarking/>, October 1997.  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... the PixelTag system by the MIT Media Lab and the SysCop system from Zhao and Koch of the Frauenhofer Institut fur Graphische Datenverarbeitung [39,40] Many of these systems have been subject to attacks, that destroy the marking or at least reveal significant limitations of the marking techniques [2,3,17,24,27]. 3 Overview We envision the watermark system operating an open environment like the Internet with different interconnected computers. Users can be located anywhere and can sell or buy images. If legal dispute resolution for multiple watermarks 3 is needed the Copyright Holder (H) sends ....

F.A. Petitcolas, "Weakness of existing watermarking schemes'`, http://www.cl.cam.ac.uk/fapp2/watermarking/image watermarking/, October 1997.

....Internet browsers capable of filtering images containing certain marks (that would presume the existence of a standard for marking for example X rated images) automatic display of copyright information with every image, etc. Special care would have to be taken to overcome so called mosaic attack [Pet1] So far, no secure public detectors exist. 2.7 Conflicting requirements The above requirements are mutually competitive and cannot be clearly optimized at the same time. If we want to hide a large message inside an image, we cannot require at the same time absolute undetectability and large ....

F. A. P. Petitcolas, "Weakness of existing watermarking schemes",

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Fabien A. P. Petitcolas. Weakness of existing watermarking schemes. <http://www.cl.cam.ac.uk/~fapp2/ watermarking/image_watermarking/>, October 1997.

....to the original image (Fig. 4) This attack appears to be quite general; all marking schemes require the marked image to have some minimal size (one cannot hide a meaningful mark in just one pixel) Thus by splitting an image into su#ciently small pieces, the mark detector will be confused [53]. The best that one can hope for is that the minimal size could be quite small and the method might therefore not be very practical. Fig. 4. Screen shot of a web browser while downloading an image after the mosaic attack. This attack chops a watermarked image into smaller images which are stuck ....

....the mosaic attack. This attack chops a watermarked image into smaller images which are stuck back together when the browser renders the page. We implemented software that reads a JPEG picture and produces a corresponding mosaic of small JPEG images as well as the necessary HTML code automatically [53]. In some cases downloading the mosaic is even faster than downloading the full image In this example we used a 350 280 pixel image watermarked using PictureMarc 1.51. 228 There are other problems with such crawlers . Java applets, ActiveX controls, etc. can be embedded to display a picture ....

Fabien A. P. Petitcolas. Weakness of existing watermarking schemes. <http:// www.cl.cam.ac.uk/~fapp2/watermarking/image_watermarking/>, October 1997.

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Fabien A. P. Petitcolas. Weakness of existing watermarking schemes. <http://www.cl.cam.ac.uk/~fapp2/ watermarking/image_watermarking/>, October 1997.

No context found.

Fabien A. P. Petitcolas. Weakness of existing watermarking schemes. <http://www.cl.cam.ac.uk/~fapp2/ watermarking/image_watermarking/>, October 1997.

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