Maybe in theory it is safe, but implementations are often not safe.
An oversimplified way to see this is that your software runs on an OS which runs on a processor.
Your processor is backdoored (Intel ME and equivalent), your OS is backdoored, the entropy for your crypto is backdoored (Intel RDRAND instruction), your crypto algorithm implementation is backdoored.
So there are infinite resources for them to hack you at any moment for any reason. You have already gave them the keys to everything.
> The NSA is not god, they can't break 2048-bit TLS encryption no matter how many computers they have.
2048 bit TLS encryption? You mean 2048 bit RSA encryption? Also what source do you have that says the NSA can not crack a 2048 bit RSA key? Last I checked that info was non public and there is no definitive, credible source saying whether they can or can not crack 2048 RSA keys.
Yes I meant RSA key, sorry. My source is that 2^2048 is an enormous number and the time estimate for a desktop computer to crack it is in the quadrillions of years. Yes, I know the NSA has higher computing power than a desktop computer.
True, but I suppose it matters how easy/difficult it is for them to do that.