Well considering that the US nuclear launch codes were just zeros for a while

I've seen some statements that this was apocryphal.

https://foreignpolicy.com/2014/01/21/air-force-swears-our-nuke-launch-code-was-never-00000000/

Though you could argue -- since there was a point in time prior to PALs where there was no authorization system at all -- that a very functionally-similar state existed prior to the implementation of those codes.