Scytale

The Skytale (Greek: " scytale "; σκυτάλη, [ sky'talə ]: Stock ',' bar ') is the oldest known military encryption method. From the Spartans secret messages were not transmitted in clear text over 2500 years ago. To encrypt served a (wooden) stick with a certain diameter ( Skytale ).

Technical details

To post a message, the sender wrapped parchment ribbon or a strip of leather helically around the Skytale, wrote the message along the rod on the tape and then wrapped it from. The tape without the rod will be delivered to the recipient. If the tape into the wrong hands, it can not be read the message because the letters are arranged seemingly randomly on the tape. The correct recipient of the band could read the message with an identical Skytale ( a rod with the same diameter). The diameter of the rod is thus the secret key of this encryption method.

The Skytale belongs to the transposition process.

Historical Background

In his biography of the Spartan commander Pausanias, Cornelius Nepos ( Paus. 3.4 ) of such a cryptic note: Pausanias was when he stayed in the army in Asia Minor, under suspicion of plotting to overthrow, and was using a per Skytale encrypted message in the home recalled. It is believed that he had access in his capacity as guardian of the minor King Pleistarchus still on the Skytale he needed to decrypt.

Another example handed the Greek historian Plutarch. He describes in his biography of the Spartan general Lysander, like this (431 BC - 404 BC) during the Peloponnesian War could thwart an attack by the Persians. The corresponding warning was carried out in the form of a message that has been encrypted with a Skytale.

Due to their ease of use and the ( for that time ) high level of security that it offered, the Skytale was also spread in the Persian Empire. How advanced this system of letter - swapping, so the transposition is shown by the fact that transposition after the demise of classical culture emerges for the first time in the Middle Ages.