Ṣubḥ al-aʿshā
1412 AD published
Encyclopedic administrative manual on geography, political history, natural history, zoology, mineralogy, cosmography, and time measurement.
Notably, it is cited by David Kahn as the first published discussion of the substitution and transposition of ciphers, and the first description of a polyalphabetic cipher, in which each plaintext letter is assigned more than one substitution. The exposition on cryptanalysis included the use of tables of letter frequencies and sets of letters which cannot occur together in one word.
Subjects Who or What published?
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Al-Qalqashandi (شهاب الدين أحمد بن علي بن أحمد القلقشندي) Medieval Egyptian encycl...
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