[pradn]

Yes, it would have to be a perceptual hash. False positives will occur, so there needs to be a way to appeal or remediate the algorithmic decision. We already apply this approach in a bunch of places. I believe the major personal cloud storage providers (OneDrive, etc) already do such scanning.

[ApolloFortyNine]

>This can be used for CP but also for known-bad fake news or inflammatory content.

It worries me that anyone thinks it would be a good idea to have "fake news" and "inflammatory content" blocked at the device level. Obviously cloud providers can do whatever they want (though I doubt it catches any more than the lowest hanging fruit, encrypting then uploading would be uncatchable), but the idea that my device will have a list of disapproved content, and I'll have to appeal to the government to be allowed to view it in case of false positives? The day that becomes a reality freedom will truly be dead.

[pradn]

I didn't say it would be at the system level. I'd expect this to happen per app. It's similar to how photo manipulation software can detect currency. I doubt every such app complies, and certainly the system screenshot tool does not.