The whole idea of electronic security (cell/ internet) is a fool’s game. The only real security there is is plain old common sense. Its fool proof.
When you can't encrypt, fool 'em:
Kirk: Kirk to Enterprise.
Spock: Spock here.
Kirk: Captain Spock, damage report.
Spock: Admiral, if we go "by the book". like Lieutenant Saavik, hours could seem like days.
Kirk: I read you captain. Let's have it.
Spock: The situation is grave, Admiral. We won't have main power for six "days". Auxiliary power has temporarily failed. Restoration may be possible, in two "days". By the book, Admiral.