Also, we've seen more and more AI hardware being shipped built-in to phones.

I hope it's hash-based and not AI. Training that NN would be one of the worst jobs I could imagine, you're adding commercial value to child porn and all the misery it entailed.

They trained a neural net to perturb images. Not classify them.[1]

They did add a classifier to iMessage. But it's designed to prevent children seeing any sexually explicit images.[2] There wouldn't be a reason to train it on images of children specifically.

[1] https://www.apple.com/child-safety/pdf/CSAM_Detection_Techni...

[2] https://www.eff.org/deeplinks/2021/08/apples-plan-think-diff...

They are using AI techniques as part of perceptual hashing. In other words it’s trying to match files with specific images rather than abstract concepts.

I’m pretty sure you don’t know what you’re talking about. Perceptual matching is not image matching.

Perceptual matching is used to sort categories of images. A quick DuckDuckGo will turn up many results. No stretch of the imagination will turn this into a bit for a bit comparison. This is a machine learning algorithm used to categorize images. https://www.ibm.com/blogs/research/2019/10/learning-implicit...

Matthew Green is tweeting about this: https://twitter.com/matthew_d_green/status/14230711866160005... and mentions that it is "preceptial hashing”

9 to 5 Mac article, in which they restate that it is not a classical bit-by-bit hash:

https://9to5mac.com/2021/08/05/scanning-for-child-abuse-imag...

Perceptual hashing has a very specific meaning. It’s for verifying one file is directly related to a different file not an overall classification.

“Perceptual hashing is the use of an algorithm that produces a snippet or fingerprint of various forms of multimedia.[1][2] A perceptual hash is a type of locality-sensitive hash, which is analogous if features of the multimedia are similar.”

https://en.wikipedia.org/wiki/Perceptual_hashing

The goal is to verify a black and white copy of an image is identical to a colored original. Search algorithms want a similar thing so they can validate an image contains a blue car. However, a perceptual hashing algorithm must differentiate between different images containing a blue car while matching a photoshopped copy of the same image.