[YokoSix]

Genuine question: If those image were really generated from illegal porn, are those images themselves considered illegal? Or in other words: How much do you have to modify illegal images for them to become legal again? Or do they stay illegal no matter how much you transform them?

[f38zf5vdt]

Looking at the script below, it looks like it uses a gradient function for loss so that it learns to approach an image that generates a collision. If the case that the hashes themselves, being a result of a neural network, can be reverse engineered into pornographic images then does that raise a legal quandary?

Apple said that the risk of collision is "1 in one trillion" which for a hash function would be terrible. We also don't know what the one trillion images they tested against were. If you upload your regular porn to iCloud, it's likely that pornographic images will raise more false positives than say, pictures of sunsets.

[d35007]

Apple said that the probability of a collision is quite a bit higher than that:

> As the system is initially deployed, we do not assume the 3 in 100M image-level false positive rate we mea- sured in our empirical assessment

The "1 in 1 trillion" part is the probability that the number of false positives could exceed the threshold needed to trigger a human review:

> Apple always chooses the match threshold such that the possibility of any given account being flagged incorrectly is lower than one in one trillion, under a very conservative assumption of the NeuralHash false positive rate in the field.

source: https://www.apple.com/child-safety/pdf/Security_Threat_Model..., page 10

[Applejinx]

Also relevant question: if these images were not at all generated from illegal porn, but they connect to hashes being used to flag illegal porn, is the purpose of this exercise to generate methods to SWAT people over the internet?

As in, pursue a mechanism to get these onto somebody's computer in a way that they'll be backed up via iCloud (for instance, if a person's got their email account including trash folder backed up in iCloud, and you send them the pictures which they 'throw away' because it means nothing to them, placing the images in a trash folder in the mail preferences)

Is that (a) practical and (b) the intent of this exercise? Seeing as every question I've had here has led to karma burning I figured I'd double down and ask if the person doing this is trying to prepare a weapon for swatting people. There are times I respond to downvoting pressure to 'stop talking!' by getting more interested, which I'm sure is a common reaction among some hackers.