What is on the sheet
At the top, the alphabet in two rows with an empty box under every letter: that's your key. Below it, five rows of letter spaces, each with a box underneath for the coded letter or symbol, and lines for who it's from and who it's for.
Ways to fill in the key
A Caesar shift. Write the alphabet again, moved along: with a shift of 3, D goes under A, E under B. The Caesar cipher wheel shows every shift.
A keyword. Write a word with no repeated letters, then the rest of the alphabet in order. With the keyword KRYPTOS, K goes under A, R under B. The keyword cipher page builds the alphabet for you.
Symbols. Draw the pigpen shapes, or dots and dashes from the Morse code chart, or make up a symbol for every letter. A made-up alphabet is a substitution cipher, the kind newspapers print as cryptograms.
Whatever you pick, the friend you send it to needs the same key, or the patience to crack it.
Frequently asked questions
How do you make a secret code?
Pick a rule for swapping each letter for another letter, number or symbol, write it down as a key from A to Z, then code your message one letter at a time. Give the key to the person you're writing to.
What are easy secret codes for kids?
A Caesar shift, pigpen, and A1Z26, where each letter becomes its place in the alphabet (A is 1, Z is 26), are the easiest to start with. Morse code is a good next step.
Can I use this worksheet for any cipher?
Any cipher that swaps one letter for one thing, which covers Caesar, Atbash, keyword, pigpen, Morse and anything you invent. Codes that change as they go, like Vigenère, need the message written out longhand.
Covert Mail on your phone
Covert Mail teaches fifteen codes, from Morse and pigpen to the Vigenère cipher, and sends a coded message to a friend as a link, with the key or without it. It's free on the App Store.
Download on the App Store▶ Coming soon to Google Play
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Print the Caesar cipher wheel or the pigpen cipher key to go with it. There's more on the printables page.