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Then that's a different photo and will have a different hash.
by fossuser 5y ago
Then that's a different photo and will have a different hash.
- Simucal 5y agoThese aren’t cryptographic hashes. They are perceptual hashes and a picture of a picture could absolutely end up with the same phash value.
- skavi 5y agois there really no fuzziness to it? If not, can’t this be defeated by simply reencoding the image?
- fossuser 5y agoI think it has gotten more sophisticated to detect cropped images and small changes now: https://inhope.org/EN/articles/what-is-image-hashing https://inhope.org/EN/articles/what-is-image-hashing The example is somewhat contrived. If a 'friend' takes your phone and has access to it and then uses it to take images of CSAM similar enough to the original image that it triggers the hash match and does this enough times to go over Apple's threshold to flag the account after these images are uploaded to icloud without the original phone owner noticing then yes it might cause a match. At that point the match is probably a good thing (and not really a false positive anyway) - since it may lead back to the friend (that has the illegal material).
- zbobet2012 5y agoOr you know, anyone who wants to plant material on a device and has physical access. Say a disgruntled employee before leaving, or ex, or criminal or... Or anyone who can just text you since imessage backs up to icloud automatically...
- jeromegv 5y agoWhile iMessage backups to iCloud, this measure is only for photos stored in the iCloud Photo Library. So sending a text with the photo is not enough.
- deleted 5y ago[deleted]
- antpol 5y agoAre you sure the hash function literally called "NeuralMatch" running on the device with 2+ gen of AI capable chips won't have "collisions"?