David Kahn notes in The Codebreakers that Arab scholars were the first people to systematically document cryptanalytic methods.

The first known recorded explanation of cryptanalysis was given by Al-Kindi (c. 801-873, also known as "Alkindus" in Europe), a 9th-century Arab polymath, in Risalah fi Istikhraj al-Mu'amma (A Manuscript on Deciphering