Roman Cybersecurity: The Scytale

Benjamin Rhodes
#TechIsATool
Published in
6 min readMar 21, 2020

Security is a fundamental concept in modern computing. However, most don’t realize it originated thousands of years ago in the Roman Empire.

The year is roughly 700 BC. The Romans are taking the world by storm, literally. They prove themselves to be one of the most powerful conquering armies in history, taking control of most of the known civilized world. They went on to contribute much to our modern world. They invented aqueducts to quickly move water and paved roads allowing for safer and easier travel. The Romans are also claimed to have introduced stadiums, plumbing, and new methods of science and art. However, known to few is their impact on modern day computers and digital security.

Consider this scenario. The powerful Roman army is marching into new territory to conquer. For strategy, information sharing, and even safety they must communicate to the rest of the army. What methods do they have? This is 700 BC, phones and email won’t do. They could write a letter, but what if the enemy captured the messenger? There goes any strategy, private information, or safety. They could send an entire battalion to protect the message, but that would compromise speed and ease of movement.

In writings that date back to 680 BC — 645 BC, Archilochus tells of a device and method of encryption used to easily transport, deliver, and communicate (Garfinkel and Grunspan 18). 700 years later, in the writings of Plutarch, we learn that the Scytale was used as a method of secure communication (Garfinkel and Grunspan 18). With the Scytale, came the birth of devices that simplified, complicated, and toughened encryption while paving the way for modern data security.

The device was called the Scytale, one of the first cryptographic devices (Garfinkel and Grunspan 18). Methods of encryption are known to have existed before, but were only methods to hide information as opposed to a quick device. The Scytale was simple, it involved only a stick, it could have been wooden or really anything round, and a long strip of leather or parchment on which to write a message.

In order to use the device the sender and recipient would need to have a wooden stick or round object the same diameter. The diameter essentially became what is now called an encryption key (Garfinkel and Grunspan 18). An encryption key is the primary piece of an encryption. It is used to encrypt and decrypt the message and is therefore highly secured because it is the only method by which to read the message. The message was only securely sent separated from the wooden pole or device. If someone intercepted the message and wrapped it around a different sized object, they could not easily decipher the message.

The Scytale worked as so. The sender would take their strip of leather or parchment and wrap it around the object (see Figure 1).

They would then write their message lengthwise across the parchment, each letter would be on its own strip of the parchment (see Figure 2).

Then, the parchment would be removed from the wooden pole. In this orientation, the message would appear as a jumbled collection of letters (see Figure 3).

If someone intercepted the message and wrapped it around a differently sized object, the letters would not line up and the message could not be easily read (“Classical Cryptography”).

At the receiving end, the recipient would have a wooden pole of the same diameter and would simply reverse the process. They would wrap the parchment around the pole and then easily read the message (“Classical Cryptography”).

In and of itself, the Scytale wasn’t a particularly secure way to send messages. The only thing that truly kept the message secure was the diameter of the pole. However, combined with other cryptographic methods invented earlier in Egypt, Mesopotamia, and Judaea, the Scytale could add enhanced security to an encrypted message (Garfinkel and Grunspan 18).

As with the Sumerian Abacus discussed last week, the Scytale encryption device was born from need. The Romans required a more secure method to communicate without their enemy understanding the communication. They also had a second need. In war, communication must be quick and relatively easy to encrypt and decrypt. Speed is key and could decide a battle. Therefore, the Scytale met both of these needs.

As with the Sumerian Abacus discussed last week, the Scytale encryption device was born from need.

We also see the part war places in the history of computing. War is often a necessary evil. If anyone said they enjoyed war, we might think they should be examined. Yes, we would all prefer peace, but in a world of sin that is simply not possible. However, although war causes much damage, destruction, and of course, violence. It’s role in the advancement of technology is profound. Wait until we reach World War I and World War II, two eras of American history when the use of new invention and technology exploded. If the Romans had not been fighting or did not otherwise had a need to securely communicate, it could be assumed that encryption of any kind would not have been invented or would have been slower to develop.

We also see the part war places in the history of computing.

We live in a time where the importance of data security and private communication is vital and well understood. Over the years, millions of lives have been changed from identity theft and billions of dollars have been lost to credit card fraud and other illegal actions. Facebook has been attacked for its handling of private data and large corporations are finding themselves at the sharp end of consumer and governmental pressure to keep our data secure. At the center of all these debates is data encryption.

Although data encryption looks far different than it did in 700 BC, it was, and is, no less needed, important, and vital during both eras. As simple as the Scytale is, it’s invention paved the way for greater, more sophisticated, and complex methods of encryption. Before the car could be invented, the wheel had to be created.

As simple as the Scytale is, it’s invention paved the way for greater, more sophisticated, and complex methods of encryption.

Thanks for tuning it today, I apologize if this week’s blog is a little shorter, but the Scytale is a simple device and when you’re researching devices thousands of years old there can be little information available. The Scytale is the second major milestone in computing history, did you guess it correctly? Next week we’ll be discussing a very influential, advanced, and famous piece of computing history. Let me know below, or on social media, if you can figure out what it is!

Until then, follow me on social media, subscribe to my YouTube channel, and stay engaged. See ya next week!

Works Cited

“Classical Cryptography.” URI.edu, University of Rhode Island, www.cs.uri.edu/cryptography/classicaltransposition.htm.

Garfinkel, Simpson L. and Rachel H. Grunspan. The Computer Book: From the Abacus to Artificial Intelligence, 250 Milestones in the History of Computer Science. Sterling Publishing Co., Inc., 2018.

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Benjamin Rhodes
#TechIsATool

Technology is a tool used for good or bad. Join me on YouTube and Medium as I explore how technology can be used to better our world.