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While stego might be a route, blurring the watermark may not be enough to obscure the source. Given a known frame, they could blur the same portion of the same
by madaxe_again 12y ago
While stego might be a route, blurring the watermark may not be enough to obscure the source.
Given a known frame, they could blur the same portion of the same frame on all watermarked copies, and the one with a matching output is your culprit.
Blurring loses information, but is more akin to a hash than a deletion, as it's a deterministic process.
Edit: this sort of thing. http://dheera.net/projects/blur http://dheera.net/projects/blur
- peeters 12y agoIt's a deterministic process, but it still has inputs. You'd have to know those inputs or test for every possible set of inputs to whatever blurring method was used.
- spb 12y agoI imagine HBO knows every reviewer they gave a watermarked copy to.
- darkmighty 12y agoIt depends on the blurring method. If you do a gaussian blur, for example, you might be able to do a pretty good inverse blur by finding black frames and performing blind deconvolution. If I were at risk I'd use a nonlinear injective filter instead, to make sure information is lost (linear filtering is not only deterministic but perfectly without noise and no frequency response nulls).