I was watching a lecture on the power method. Formally, it delivers approximate solutions to figuring eigenvalues of expander graphs – those found in the cryptanalysis solutions for wiring plans (think des, think enigma) of keyed rotor machines.
Whether its nash math, for constraint satisfaction in economics or crypto, or solution approximating based on rationale numbers and rayley quotients, its just fascinating to see how the core “super secret” world if cryptanalytic technique has been sitting open fie a long time. Its just that our eyes were *forced * closed, so we could not see.
Fascinating also to consider how Turing – the cryptanalyst turned cipher designer – knew how to defend against guessing attacks, assuming complexity and capabilities of attack machinery based in industrial capacity of an economy etc