Portal:Cryptography/Did you know

From Wikipedia, the free encyclopedia

...that the Pigpen cipher was used by the Freemasons for correspondence and record keeping?
...that Polish mathematician Marian Rejewski (pictured) deduced the wiring of the German Enigma machine in 1932 using theorems about permutations?

...that acoustic cryptanalysis is a type of attack that exploits sound in order to compromise a system?
...that one scheme to defeat spam involves proving that the sender has performed a small amount of computation: a proof-of-work system?