There's no future-proof suggestion that's immune to the government declaring it a crime.
If you want a suggestion for secure messaging, it's Signal/WhatsApp. If you want to LARP at security with a handful of other folks, GPG is a fine way to do that.
If you want a suggestion for secure messaging, it's Signal/WhatsApp. If you want to LARP at security with a handful of other folks, GPG is a fine way to do that.