Re: How can Facebook be encrypted end to end?
Apple wanted to do that (checking CSAM on the iPhone, before it was uploaded to iCloud), that kicked up such a stink about the sanctity of the personal device, that they have put the plans on hold, for now.
The problem isn't just CSAM, it is, if you start looking for CSAM, why not look for homosexual images for certain Eastern Block countries? Or anti-government posts in China? Or anti-royalist comments in Thailand? Anti-abortion talk in the USA?
Here, in Germany, the Constitutional Court backs E2EE and the state has to get a search warrant and install the "Staatstrojaner" on suspects devices in order to monitor messenger traffic.