At-Home Activity: Encryption with the Pigpen Cipher

At-Home Activity: Encryption with the Pigpen Cipher


Today's activity touches on encryption and decryption, common tasks all cybersecurity professionals must be familiar with, though today's version is much, much, MUCH simpler than current methodology.

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So what is encryption?

Encryption is using a code to hide a message or information so people need a key or password to read it. All secure electronic communications use complex encryption methods to keep data secure.

We're using the pigpen cipher (also known as the masonic cipher, Freemason's cipher, Napoleon cipher, and tic-tac-toe cipher), which is believed to be an ancient cipher. The pigpen cipher assigns geometric symbols - representing the fragments of a grid - to the letters of the alphabet.

It looks like this...

Pigpen cipher full

Thought fairly easy to crack, the pigpen cipher teaches how modern-day encryption works. A message comes in, something like this...

Pigpen Test Cipher

An encrypted message comes in, usually a combination of letters and numbers and is run through a decryption key, revealing the original message and ensuring the content is protected from prying eyes.

So how does this work?

Let's take the first symbol,

Pigpen H

Notice that they look similar to the shape of the bracket for the "GH" section. This means that the symbol represents one of those letters. How do you know which one? You need something that notes one letter rather than another. The dot inside the shape means the second letter. The same applies to the X-shaped bracket.


Pigpen Overlay

The dot on the symbol indicates to use the second letter. So the second letter

Pigpen E

represents an "E". Can you decipher the rest of the secret message?

Here are some more phrases to encrypt and decrypt! Feel free to encourage your students/children/friends and family to leave secret messages for you around the house!

We'll keep posting material this week. Feel free to reach out to us at for any additional assistance or resources in these difficult and uncertain times. We're here for you!

Stay safe out there!

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