So far I enjoy secret codes more than any of my sons, but they are handy for birthday party treasure hunts, etc.

This is a symmetrical cipher, which is the most fun for kids to use because the encryption an decryption steps are the same. 'A' translates to '', and '' translates back to 'A'.

A secret code

Note that if you leave this page and come back later, the code will change. Write it down if it's important, otherwise you'll be following these directions.

If you're under a time constraint, you can use this utility to encode or decode your message. Put either the plaintext or the cryptotext in the box on the left and click the button. (It's symmetric, so the encryption and decryption process is the same.)

Set a new code

Enter the letters corresponding to ABCD...XYZ: (This assumes you've set up a proper symmetrical substitution cipher.)

An actual secret decoder

If you're a LaTeX user, you might be interested in a document I created to make an actual secret decoder ring, like like this one. You cut out the two circles, cut out the square holes, attach the pieces of paper with a brad, and you're set. (It's more fun, but not necessarily more productive!) You can use the example, or create your own with this LaTeX file. It uses Tikz. To get the code for the current page into the .tex file, paste the text below into the .tex file where appropriate. (There is a place in the tex file that looks like what's below, but with a different code. Leave everything else untouched.)

All contents copyright © 2018 Adam Baker, except where otherwise noted.