[red_admiral]

During the cold war, the Washington-Moscow "nuclear" hotline was set up with teleprinters and one-time pad keys for both directions. I imagine they had an analogue randomness key generator on both ends to generate the key material.

Presumably they're using ~Dual-EC DRBG~ some kind of quantum randomness generators these days.

[pvg]

There was, interestingly, a much fancier system used quite a bit earlier

https://en.wikipedia.org/wiki/SIGSALY

https://news.ycombinator.com/item?id=20138230

[red_admiral]

> The noise values used for the encryption key were originally produced by large mercury-vapor rectifying vacuum tubes and stored on a phonograph record.

That's sure a hardcore way to run an analogue randomness generator.

[pvg]

The beta decay enthusiasts were busy elsewhere.