Because as other mentioned before its just few lines of code away to allow scanning any pictures that are not synced to any cloud. This just puts foundation for cheap, automatic mass surveillance.
Imagine if you were hired to design mass surveillance system. What kind of technical problems you would have to face?:
1) Trillions of pictures of altogether huge MB of data would have to be send to your servers to analyze - this creates huge network badwidth
2) You would need huge computing power to analyze those
3) This would probably easy to be detected
Apple solution would allow:
1) plausible deniability - it 'was just a bug that scanned all pictures instead of those that supposed to be in icloud'
2) cheap - using user cpu/gpu and smaller user bandwidth just to send hashes
3) less suspicions than having completely unknown process/daemon in the background because rolled as part of 'protect the children' campain
4) rolled out to one of the most popular mobile phone in US that has locked bootloader and OS cannot be downgraded, etc.
Great explanation.
It’s Apple way of decentralized image analysis with very little server cost and this is the most amazing idea I’ve seen for mass surveillance
