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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water-clocks The water-clocks are an early long-distance-communication-system. Every communicating party had exactly the same jar, with a same-size-hole that was closed and the same amount of water in it. In the jar was a stick with different messages written on. When one party wanted to tell something to the other it made a fire-sign. When the other answered, both of them opened the hole at the same time. And with the help of another fire-sign closed it again at the same time, too. In the end the water covered the stick until the point of the wanted message.

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