3 ms·
Cryptographic hashes are exactly not trivial to "dupe". https://en.wikipedia.org/wiki/Cryptographic_hash_function https://en.wikipedia.org/wiki/Cryptographic_h
by jjtheblunt 5y ago
Cryptographic hashes are exactly not trivial to "dupe".
https://en.wikipedia.org/wiki/Cryptographic_hash_function https://en.wikipedia.org/wiki/Cryptographic_hash_function
that said, it's not clear to me from
https://www.apple.com/child-safety/pdf/Apple_PSI_System_Security_Protocol_and_Analysis.pdf https://www.apple.com/child-safety/pdf/Apple_PSI_System_Secu...
how collision resistant what's to be used will be.
- pseudalopex 5y agoPerceptual hashes aren't cryptographic.
- handoflixue 5y agoIs there anything stopping them from using an actual cryptographic hash, though?
- pseudalopex 5y agoEven the smallest change to an image changes a cryptographic hash.
- layoutIfNeeded 5y agoUmmm… the fact that changing a single pixel will let the baddies evade detection?
- heavyset_go 5y agoYes, using cryptographic hashes prevents them from fuzzy matching and the algorithms that allow for efficient matching and fuzzy matching require comparing the bare hashes.
- kickopotomus 5y agoThey are not using cryptographic hashes. They are using perceptual hashes[1] which are fairly trivial to replicate. [1]: https://en.wikipedia.org/wiki/Perceptual_hashing https://en.wikipedia.org/wiki/Perceptual_hashing
- tcoff91 5y agoThis seems dumb. I'm sure that sophisticated bad people will just alter colors and things to defeat the hashes and meanwhile trolls will generate collisions to cause people to falsely be flagged.
- judge2020 5y agoThe perceptual hashes are specifically designed to correlate images that are visually similar while not being exactly alike, even when the colors are altered. See: https://blog.cloudflare.com/the-csam-scanning-tool/ https://blog.cloudflare.com/the-csam-scanning-tool/
- deleted 5y ago[deleted]