Timeline BC ~ 1900 BC: Egyptian writers use non-standard Hieroglyphs in inscriptions of a royal tomb; supposedly this is not the first but the first documented example of written cryptography 1500 an enciphered formula for the production of pottery is done in Mesopotamia parts of the Hebrew writing of Jeremiah's words are written down in "atbash", which is nothing else than a reverse alphabet and one of the first famous methods of enciphering 4th century Aeneas Tacticus invents a form of beacons, by introducing a sort of water-clock 487 the Spartans introduce the so called "skytale" for sending short secret messages to and from the battle field 170 Polybius develops a system to convert letters into numerical characters, an invention called the Polybius Chequerboard. 50-60 Julius Caesar develops an enciphering method, later called the Caesar Cipher, shifting each letter of the alphabet an amount which is fixed before. Like atbash this is a monoalphabetic substitution.

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Alan Turing b. June 23, 1912, London, England d. June 7, 1954, Wilmslow, Cheshire English mathematician and logician who pioneered in the field of computer theory and who contributed important logical analyses of computer processes. Many mathematicians in the first decades of the 20th century had attempted to eliminate all possible error from mathematics by establishing a formal, or purely algorithmic, procedure for establishing truth. The mathematician Kurt Gödel threw up an obstacle to this effort with his incompleteness theorem. Turing was motivated by Gödel's work to seek an algorithmic method of determining whether any given propositions were undecidable, with the ultimate goal of eliminating them from mathematics. Instead, he proved in his seminal paper "On Computable Numbers, with an Application to the Entscheidungsproblem [Decision Problem]" (1936) that there cannot exist any such universal method of determination and, hence, that mathematics will always contain undecidable propositions. During World War II he served with the Government Code and Cypher School, at Bletchley, Buckinghamshire, where he played a significant role in breaking the codes of the German "Enigma Machine". He also championed the theory that computers eventually could be constructed that would be capable of human thought, and he proposed the Turing test, to assess this capability. Turing's papers on the subject are widely acknowledged as the foundation of research in artificial intelligence. In 1952 Alan M. Turing committed suicide, probably because of the depressing medical treatment that he had been forced to undergo (in lieu of prison) to "cure" him of homosexuality.

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