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A comment on One woman's struggle to remove all traces of videotaped sexual assault. Parent comment

Re:One woman's struggle to remove all traces of videotaped s... by pgsimp on Wednesday April 07, 2021 @05:12PM (#26731371)
That assumes all thumbnails or pictures hash to the same value. Why would that be? There can be different algorithms, resolutions, crops... And there can be millions of thumbnails to check.
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Re:One woman's struggle to remove all traces of videotaped s... by zepto on Thursday April 08, 2021 @04:48PM (#26743570)
> That assumes all thumbnails or pictures hash to the same value.

The same set of values, yes.

> Why would that be? There can be different algorithms, resolutions, crops...

Yes, so you do normalization and reduction before computing the hashes.

And ‘hashes’ doesn’t have to mean literal SHA. Any non-reversible fingerprinting algorithm will do.

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Re:One woman's struggle to remove all traces of videotaped s... by nunez on Wednesday April 07, 2021 @06:25PM (#26732280)
Yeah it's a gnarly problem for sure. I mean I'm sure doing some sort of hash-based blocking would knock out 80% of the content related to a takedown request, but I could also see that last 20% being difficult af to purge.

the internet definitely remembers forever, unfortunately, especially porn

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