“Establishing secure means of communication, etc.”
Become a amateur radio operator. All sorts of alternative means of communication is available then.
You have Morse Code, radio teletype, packet radio, voice, bouncing signals off of the Moon and amateur radio satellites in orbit (known as the OSCAR satellites), etc.
Jack, I am fascinated. Any advice how to get started? I always wanted to learn Morse code but I could really get into bouncing signals off the moon to help the conservative cause even though I’m a girl.