Greek Myths XS: Cryptography in Ancient Times

The term “diplomacy” derives from the Greek “diploma”, a folded document that granted immunity to messengers. These keyworkers had a challenging job. Emperor Nero for example, had the habit of providing his messengers with an obscene password, just for the fun of getting them into trouble. To keep their messages secret, the ancients were quite inventive. The tyrant Histiaios shaved the head of a slave, wrote a message on it and sent the slave on its way when the hair had grown back, only to be shaved off again to reveal the writing. More subtile forms of cryptography are the Spartan “skutalon”, a cylinder with a strip of parchment wound around it, and the well known “Caesar cipher”, based on substitution. More complicated was the “pyrseia table”, that used a grid, lit by torches, to send messages letter by letter. Even more advanced was the “hydraulic telegraph”: two identical devices that made use of pre-written messages, floating on an adjustable level of water.  Who needs an Enigma machine, indeed.

Hydraulic Telegraph, (reproduction),

Thessaloniki Science Center and Technology Museum, Greece

Pyrseia Table, Kotsanas Museum of Ancient Greek Technology, Greece