[1]https://en.wikipedia.org/wiki/Copiale_cipher [2]https://www.wired.com/2012/11/ff-the-manuscript/
For the amount of time and effort it took to extract this secret, that's a hilarious letdown.
> "Although certainly not as complex or secure as modern computer operated stream ciphers or block ciphers, in practice messages protected by it resisted all attempts at cryptanalysis by at least the NSA from its discovery in 1953 until Häyhänen's defection in 1957."
Wonder how it compares to: https://en.wikipedia.org/wiki/Solitaire_(cipher)
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On the mountain was a treasure
Buried deep beneath a stone
And the valley people swore
They'd have it for their very own