I have a Sister and Brother-in-Law who typically spend half the year in Europe. We email each other about every day.
Last year when I still had a dial-up modem, it got to where I had real problems sending and receiving emails from them, I guess I should change that to opening emails and sending emails just to them. None of my other regular email senders/receivers, had any problem.
I remember wondering if the fact they were in Hungary meant that someone was spying on my emails. This was before all the publicity. Of course discussing family reunions, the weather etc. would get pretty boring to anyone listening in I guess.
I bet you could dig out an old dial up modem that worked over a phone like (the 80s kind that made that screaching noise). I doubt any of the modern listening equipment would work with it.
Clever code, Comrade. Just don’t write “John has a long mustache” or all Hell will break loose.