That said, if you're using a wireless keyboard it's pretty much a given that the keystrokes can be recovered by timing analysis regardless of the manner of wireless connection. At least unless you happen to hunt and peck painfully slowly.

My father worked in defense. He shared lore about the genesis of tempest, the requirement to use faraday cages to protect secrets, gear, etc.

The story goes that some kind of red team set up shop down the road from some missile tests (or something) with some simple gear. Afterwards, they shared the launch codes used, shocking all the brass. Hence the need for shielded comms.

An interesting read is Spy Catchers written by first science officer from MI5 in cold war. he was tasked with reversing listening devices and making them.. it doesnt spill all the beans but givea a good insight into how far they were already then.

u can hardly imagine what tech exists now 40-60 years later as electronics and computers have shrunk drastically and infinitely more weird material properties are discovered....

And the Moog company, specializing in high tech products, started by a cousin of the synthesizer guy: https://en.wikipedia.org/wiki/Moog_Inc.