Welcome back, my cyberwarriors!
I truly appreciate all of the work you have done to support the brave people of Ukraine. You are all heroes!
Right now, it appears that Russia will try to take out the communication system of Ukraine including its Internet service. Although the government just implemented Starlink from Elon Musk's SpaceX (I also use Starlink). This will likely keep the government connected to the Internet except in the unlikely case that Russia takes out the Starlink satellite (in that case, things could escalate very quickly as that is an American asset and the US military would likely respond). What happens to the communications of all the ordinary Ukrainians if Russia successfully takes out there Internet access? One of the weapons that Russia has in its arsenal is an EMP or Electro-Magnetic Pulse. Such a weapon would temporarily disable all communication systems.
I have long been an advocate for a mesh-type communication system. This requires no central servers or routers. It only requires that there be a continuous, unbroken link of users within 300 feet or 100 meters of each other. In big cities, like Kyiv, that should not be an issue. In rural areas, it won't work. These systems can create their own "Internet" by connecting via Wi-Fi or Bluetooth. Messages can traverse throughout this mesh to anyone on the mesh.
A few years back, there was an app called "Firechat" that did exactly that. It played a key role in the Hong Kong rebellion when the Chinese authorities cut off Internet and cell access to keep people from communicating. This app was unfortunately discontinued in 2018.
Luckily, there is a new app that does nearly the exact same thing. It's named Briar. Its only available for Android, but since over 80% of the phones in the world use Android it should not be a problem. Its available in the Google Play app store.
When you download and install Briar, it enables you to communicate securely to anyone on the mesh network without the use of cell towers or the Internet. You messages traverse the "mesh" through secure ad hoc Wi-Fi connections (no AP needed) and/or Bluetooth. Briar's developers describe their app as:
".. a messaging app designed for activists, journalists, and anyone else who needs a safe, easy and robust way to communicate. Unlike traditional messaging apps, Briar doesn’t rely on a central server - messages are synchronized directly between the users' devices. If the internet’s down, Briar can sync via Bluetooth or Wi-Fi, keeping the information flowing in a crisis. If the internet’s up, Briar can sync via the Tor network, protecting users and their relationships from surveillance.
Although Ukraine is most acutely in need of such a communication system, it might be a good idea for all of us to have this app in the worst case scenario.