The authors of the Signal messaging system are acting as useful idiots for state security and police services: while they are almost certainly not working for them or funded by them, what they are doing is extremely convenient for them.
After WhatsApp’s threatened change to their terms of service, which may allow them to leak information to Facebook, many people are moving to Signal, a tool which purports to be more secure. If you want security which is not at least partly theatrical you should not use Signal.
Clarke’s third law is that
any sufficiently advanced technology is indistinguishable from magic.
It does not apply to organisations who want to intercept communications: if it’s claimed that they can do something which requires magic, then in fact they can’t do that.
Fog computing is like cloud computing except that no-one can see what you are doing.