Bring School of Cipher to your school

Four ways to run it

A hall full of children cracking the same message is a very good hour. Four ways to run it, for grades 2 through 5.

Assembly, 45 minutes

The animation on the big screen and one cipher broken live by the whole school.

Class workshop, 90 minutes

Every child writes and breaks their own messages, with the printed sheets to keep.

Half-day capture the flag

A whole grade competing in teams, with a scoreboard and certificates.

Six-week club kit

Everything a teacher needs to run it themselves, one cipher a week.

Ask about a visit Tell us the grades, how many children and roughly when.

What a child actually takes away

Not a list of ciphers. Three habits, and they outlast the topic.

Look for the pattern

Counting letters breaks a cipher that has more keys than there are atoms in a room. The lesson is that patience and a tally beat cleverness more often than anybody expects.

Fix the rule before you look

Take every seventh letter of any long text and words appear. If you may keep changing the rule until something turns up, you will always make something turn up, and it means nothing.

Being wrong is the work

Every cipher here can be got wrong in an obvious, checkable way. A child who spots their own mistake has learned more than one who was told.

Where it fits the curriculum

Mathematics. Shift ciphers are modular arithmetic wearing a disguise. Frequency analysis is data handling with a reason to care. Keyspace is powers and place value, and the numbers get satisfyingly enormous.

English. Acrostics, nulls and word shapes are all close reading. Writing a dull letter that hides a message is a harder composition exercise than it sounds, and children take it seriously.

History. Mary Queen of Scots, the Civil War telegraph, Bletchley, the Navajo code talkers, the BBC reading nonsense to occupied France.

Computing. Binary, hexadecimal, punched cards and the Jacquard loom, and why modern encryption holds when everything before it fell.

Design and technology. Thirteen builds with printable templates, from a scytale made of a pencil to a music box drum.

A six-week club, if you want one ready-made

Week one, pigpen. It looks like magic and needs no arithmetic. Everyone writes their name and swaps.
Week two, the shift cipher and a Caesar wheel. Build the wheel, then break one without the key by trying all twenty-five.
Week three, rail fence and a scytale. Moving letters rather than replacing them, and a key that is an object.
Week four, counting letters. Break a substitution cipher as a class, on the board, out loud.
Week five, hiding. Acrostics, a grille to cut, and invisible ink if you can face it.
Week six, capture the flag. Teams, the challenge board, and the cross-branch missions for whoever finishes early.

Everything needed is free to print, and no child needs an account or a device of their own.

The five booklets Questions people ask

What you get either way

Everything on this site is free and always will be, so a teacher can run the whole thing alone: the animations for the whiteboard, the printable pack, and the challenge board. A visit adds the noise, the teams and the certificates.

Print the sheets