Comment by chimen
4 years ago
It just gathers hashes without judging or interpreting. This is the first phase. When a child porn picture is discovered and inquired about, they just compare the hash of it with what they have on database and see who had that picture on their phone as well, allowing them to build a nicely timelined trace of it and even discover the first source.
Wouldn't their scanner be defeated by a tool that randomly modified rgba values for a small percentage of pixels in an image?
This is something that child porn enthusiasts using apple would invest their time and money into. A regular person would not think to do this (yet).