We've told our phones and computers to lock us out if anything feels off. In doubt, they validate logins against international servers, but in absence of this w

We've told our phones and computers to lock us out if anything feels off. In doubt, they validate logins against international servers, but in absence of this we have a validation stalemate. An authentication breakdown would be specially puzzling for non-technical people. Emergency personnel might find themselves shouting at very expensive bricks if authentication goes awry, and not even knowing why. I fear officials and first responders might lose access even to their institution's intranet resources because their browsers stored all their passwords. Most people don't remember anyone's cellphone, as they use messaging apps that leverage account contacts or the like. So even if local cellular networks still worked untroubled in an internet blackout, I don't think anyone who is busy in the front-line took the precaution of printing out their coworkers' phone numbers. Governments instruct their populace remotely, and even radio and TV broadcasting depends on the people who operate it having internet access. Big services like GitHub, Gmail, etc, have regional hubs that serve content locally, but I fear that they rely on centralized servers for login auth anyways and cannot possibly be functional in a vacuum. Let's use WhatsApp as an example. People rely heavily on it, and let's say we try to make it keep working as smoothly as possible to avoid disruptions in response work. Firstly, it should keep working as usual, but in lack of a proper connection it should default to a local server that you somehow set up almost overnight (let's take that for granted). Your first choice could be to convince Facebook to implement the changes themselves while everything still works, and blindly trust your country to manage delicate conversations. If they don't, you need to tell thousands of non-technical people who already have enough work on their hands how to manually install non-store apps. Google, Microsoft, Apple, etc, might help preemptively rolling out updates weakening authentication and security, but that's a very dangerous thought if it's done when not absolutely necessary. Maybe simply send notifications on how to proceed. Even if a nation instructs their populace to install a preexisting p2p app, can you guarantee the country's intranet will be still standing?