• jarfil@beehaw.org
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    3 days ago

    Depends on “how identical” is “identical”.

    The SHA hash of a file, is easy to calculate, but pretty much useless at detecting similar images; change a single bit, and the SHA hash changes.

    In order to detect similar content, you need perceptual hashes, which are no longer that easy to calculate.

    • t3rmit3@beehaw.org
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      3 days ago

      Yes, but does the law require removing similar content, or just removal of that image?

      Reading the act itself, the law requires a site to:

      (A) remove the intimate visual depiction; and

      (B) make reasonable efforts to identify and remove any known identical copies of such depiction

      So under the plain wording, similar images aren’t covered, only identical, and you only have to make a “reasonable effort” to do so, you don’t actually have to be successful in doing so. There’s nothing here that indicates perceptual hashing is required in order to meet this standard.

      And all of that aside- even perceptual hashes are not that burdensome to generate.

      • vrighter@discuss.tchncs.de
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        3 days ago

        because of the “perceptual” part.

        A normal hash has the property that it produces wildly different hashes for even the tiniest of changes in the file.

        Perceptual hashing flips that requirement on its head, and therefore makes finding a suitable hash function much harder.