Cryptology for Kids




A code is a system of symbols, letters, words, or signals that are used instead of ordinary words and numbers to send messages or store information. A code is used to keep the message short or to keep it secret.


Codes and ciphers are forms of secret communication. A code replaces words, phrases, or sentences with groups of letters or numbers, while a cipher rearranges letters or uses substitutes to disguise the message. This process is called encryption or enciphering.  The science that studies such secret communication is called cryptology.



How is cryptology used?


Secret writing has been employed about as long as writing has existed. Codes have been used throughout history whenever people wanted to keep messages private.   Cryptology has long been employed by governments, military, businesses, and organizations to protect their messages. Today, encryption is used to protect storage of data and transactions between computers.   Visit this site to learn more:


In ancient times when messages were carried by foot for miles, kings and rulers would encrypt the letters they would send to allies.  This helped to protect the secrecy of the message in case they were stolen.  In early American history, even George Washington sent coded messages to his fellow soldiers.  Likewise, the members of the Continental Congress also encoded their documents.  When the telegraph was invented, the “Morse Code” was used to send understandable messages via sound patterns. 


Today, computer users encrypt documents, network space, and e-mail messages as a way to protect the confidentiality of their messages.  The new types of encryption are very advanced, and sometimes complicated….but, the basic skill remains true to the ancient methods!


Below you will find a collection of links on cryptology use through history.

         Morse Code:

o       Visit this website to translate (and listen to!) your own message in Morse Code:


         Navajo Code Talkers in WWII:

o        Visit this site to read more about these important Americans and their role in our victory during WWII:


          ENIGMA in WWII:

o       Learn more about the code machine, ENIGMA, cracked by the Allies in WWII


          Secret Code Breakers Through History:

o       This site contains many stories about the role of encryption in history.


Calling all cryptologists!

Your mission (should you choose to accept it) is to encrypt the message the following message using at least 3 different secret codes.  Write your responses on a separate piece of paper.

Message to Encrypt:  

The red balloon will launch at noon tomorrow.  Alert all parties!


Helpful Resources:

The following links will provide you with an assortment of sample encryption techniques.  Be sure to explore them all!

         Numbers Stand for Letters




         Pigpen Ciphers  


         Mixed Up Alphabet 


         Police Letters Alphabet


          Morse Code Letters



FUN Cryptology Projects for YOU to Try:

National Security Agency’s Code Challenge:
Visit this site to begin your journey as a secret agent for the federal government.  Click on the “Start Puzzle” button to begin.

Mirror Writing:
If you hold up to a mirror something with writing, the writing looks reversed. You can easily write notes and other things to look like mirror writing. Get a sheet of thin white or light colored paper. With a dark marker, write something on one side. Make sure you write it thick and dark enough so that it will show through on to the other side. Flip over the paper and trace what you wrote. You'll be tracing it backwards. It should come out like how you would see your regular writing if you were to hold it up to a mirror. For fun, write down different words, or write a note to someone, then reverse it and send it to them.

Invisible Ink:
If you write with white crayon on a white piece of paper, it looks like there's nothing there. But if you then paint over it, your invisible writing will magically appear. Write words, phrases or even a note to someone, and then impress them by making it magically appear!

Cryptograph Wheel:
You can make a special Cryptograph Wheel to solve cryptographs (see the picture!) First make two circles of cardboard, one a bit smaller than the other, and use a protractor to mark them off into 26 pieces of about 13.8 degrees each. Write one letter of the alphabet in each division on each wheel. Then attach the two wheels together using a split pin so that you can rotate them independently.   Visit this site again to see an example:

American Sign Language:
Use this site to learn more about signing the alphabet.   You can learn how to spell words.  Enter a word into the box and press "translate" to see how it looks in the sign language. Each finger represents a letter.

Pin Marks:

Using a newspaper or a sheet of paper.  Use a pin to make tiny holes under specific letters to spell out a secret message.  To decipher the message, hold the paper up to a light (or window) and write down the marked letters.