Ancient Cryptography: The Scytale

This article is the first of a series of informative articles I plan to make on ancient forms of cryptography

In our modern times where cryptographic hashes and encrypted communications are ubiquitous, it's easy to get lost in the complexities of cryptography. But it was not always this way. Cryptography has been around since the times of the Greeks and Romans, and possibly even before that. The fact is, that there always was an advantage to keeping "the enemy" in the dark. Because of this, many, what we would consider "primitive" forms of cryptography, were invented and employed. Because there where no computers around, which would have been able to crack most of their ciphers in an instant, many simple cryptographic tools thrived.

One such ancient tool of cryptography was the Greek Scytale. The Scytale took the shape of a wooden rod of uniform diameter as well as a duplicate rod with the exact same dimensions. The Scytale allowed encrypted messages to be sent between two people if each possessed the same diameter rod. The diameter of the rod acted as a sort of cryptographic key, and would have been decided on before hand.

The way a message would have been encoded was remarkably simple. A leather strip would have been wrapped around the rod so that it did not overlap with itself (as in the picture). A message could then be inscribed horizontally on the leather strip, across the length of the rod. Once the message was written, they simply unwrapped the strip, and suddenly it would appear that nothing but gibberish was written on it. However, as soon as the leather strip was wrapped around the matching Scytale, the message would be revealed.

The Scytale was often used to send military correspondences, in order to communicate battle plans without the risk of enemy spying. Because of the messages unremarkable form (a strip of leather) it was often worn as a belt by the courier with the letters facing inwards, so as to not attract suspicion.

The Greek Scytale is definitely a remnant of a simpler time, though none the less ingenious.

Thanks for reading, I hope you found this as interesting as did, and I hope to keep these coming!