What is a secret code?
A secret code turns normal text into something unreadable at first glance, following a fixed rule. Whoever knows the rule – the key – can turn the message back. That is exactly what makes secret codes so exciting for children: you own a secret that others cannot easily crack.
The idea is ancient. The Spartans wrapped leather strips around a rod, Julius Caesar shifted letters along the alphabet, and Freemasons hid letters in pieces of a grid. All of these can be rebuilt today in minutes with paper and pencil.
Six secret codes with an example
Each card shows what the word TREASURE becomes. A click takes you to the generator with that code selected.
Symbols
Every letter becomes a sign: shapes, pigpen or animals.
TREASURE → Try it →Number code
A = 1, B = 2 … Z = 26. With optional offset and separator.
TREASURE → 20-18-5-1-19-21-18-5Try it →Caesar
Every letter moves along the alphabet. With a cipher wheel to craft.
TREASURE → WUHDVXUHTry it →Mirror writing
Real mirrored lettering. Hold a mirror next to it to read.
TREASURE → TREASURETry it →Morse code
Dots and dashes like a radio operator. A slash separates words.
TREASURE → - .-. . .- ... ..- .-. .Try it →Backwards
The text is written back to front, as a whole or word by word.
TREASURE → ERUSAERTTry it →
Which code for which age?
- From 7: symbol cipher and number code. Looking things up in the table is enough.
- From 8: mirror writing and backwards writing. They need lateral thinking but no key.
- From 9: Caesar and Morse. Both have a rule you must understand and apply.
Tips for parents and teachers
Start with a short message of three to five words. Hand over the key separately – hidden in another room, say. For groups, use the blank key sheets: every child writes their own and swaps with a neighbour.
If you received a puzzle and are stuck, Decode a secret code has a decoder for all six codes.