> Apple says: "The threshold is set to provide an extremely high level of accuracy and ensures less than a one in one trillion chance per year of incorrectly flagging a given account."

I'd rather have evidence for that statement first, since these are just funny numbers. I couldn't find false-positive rates for PhotoDNA either. How many people have been legally affected by false positives so far, how many had their images viewed? The thing is, how exactly the system works has to be kept secret, because it can otherwise be circumvented. So these technical numbers will be unverifiable. The outcomes will not, and this might be a nice reason for a FOIA request.

But who knows, it might not matter, since it's a closed source, effectively uncontrollable program running soon on millions of devices against the interest of their owners and no one is really accountable so false positives can be treated as 'collateral damage'.