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Cake day: July 16th, 2023

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  • sus@programming.devtoScience Memes@mander.xyzElsevier
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    14 days ago

    I wonder if it’s common for those steganography techniques to have some mechanism for defeating the fairly simple strategy of getting 2 copies of the file from different sources, and looking at the differences between them to expose all the watermarks.

    (I’d think you would need sections of watermark that are the same for any 2 or n combinations of copies of the data, which may be pretty easy to do in many cases, though the difference makes detecting the general watermarking strategy massively easier for the un-watermarkers)









  • sus@programming.devtoScience Memes@mander.xyzAnother day another dollar
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    2 months ago

    a shadow is just a silhouette cast on a surface, so it can move much faster than light. An object moving near the speed of light in front of a small light source that casts a shadow on a very large, very distant object could appear to move billions of times faster than light (though you would need an extremely bright light source for the shadow to be noticeable to the naked eye)

    there’s really no upper limit, just how far you’re willing to stretch the definition of “shadow” and “movement”










  • They could do it without recompilation, but something like changing the obfuscation and recompiling for every copy would likely make it much harder to get rid of the watermarks even if you can compare several different copies

    (though they could also have multiple watermarked sections so that any group of for example 3 copies would have some section that is identical, but still watermarked and would uniquely identify all three leakers. The amount of data you need the watermarks to contain goes up exponentially with the amount of distinct copies, but if you have say 1000 review copies and want to be resistant to 4 copies being “merged”, you only need to distinguish between 1000^4 combinations so you can theoretically get away with a watermark that only contains about 40 bits of data )