I heard that they require plaintext data to work. What are the other factors to this?
There is no real technical reason. They could be. It’s just a matter of encryption while in transit and no logs. Proton does it.
The real reason they aren’t, is that there’s not much incentive to make them private. The data is somewhat valuable, so hold on to it.
CallMeAl@piefed.zip 2 hours ago
Nearly all are run by companies making money by recording as much of your data as possible.
A commercial cloud app could be entirely private but then the company would not be able to take your data.