Craft a Secret Message Card

Before you begin, introduce your child to three key words:

Encryption: writing a message in code.

Decryption: unlocking the code and figuring out the message!

Cipher: the code used to encrypt and decrypt messages.

First, cut out a rectangle from a paper grocery bag. Fold it in half to create your card. 


To create your cipher, trace and cut out four identical cardboard circles. Use the marker to divide three circles into eight roughly equal segments and to divide the fourth circle in half. Label each segment with a different letter from the alphabet. At random, mark one letter on each circle with a small black dot.

Punch a hole through the center of the circles and place a paper fastener through each hole.

Using a pencil and your circular object, trace four circles onto your card. This is where you will attach your cut-out circles. Be sure to leave space between the circles for when you write your numbers.

Punch a hole through the centers of each circle on the card. Using the paper fasteners, attach your four cut-out cardboard circles to the front of the card.

Write numbers (One through 26) around each cardboard circle so that one number corresponds to one letter. Then randomly mark one number with a black dot. To see the code you created, line up the letter segments marked with dots to the numbers marked with dots — you’ve created your very own code!


To encrypt your message, first write it on a scrap piece of paper. Then use your cipher to figure out which number corresponds with each letter. When you have everything worked out, draw blank spaces on your card for each letter and write the corresponding number below each space. Give your card to a friend or family member and see if they can crack your code!