How the pigpen cipher works
The pigpen cipher uses two noughts-and-crosses grids and two large crosses. The letters A to I go in the first grid, J to R in the second grid with a dot in each space, S to V in the first cross and W to Z in the second cross with dots. To write a letter, you draw the lines around its space, adding the dot if it has one.
So A, in the top-left corner of the first grid, is drawn as a right angle with lines on its right and bottom. E, in the middle, is a closed square. J looks like A with a dot inside. The key under the tool shows every letter.
Using the translator
Type a message and it is drawn in pigpen as you type. Press Save as picture to download it as an image you can print, put in a card or use in a treasure hunt.
To decode a pigpen message, tap the matching symbol for each shape in turn and the letters build up underneath. Use Space between words and Delete to undo a mistake.
History
The pigpen cipher is also called the Freemasons' cipher, because Freemasons used it in the 1700s to keep their records private. It has appeared on gravestones, in games and in books ever since. Versions differ slightly in how the letters are laid out in the grids, so if a message will not decode, the writer may have used a different arrangement.
Questions and answers
Why is it called pigpen?
The letters sit in little enclosures like pens, and the grid is said to look like a set of pigpens.
Is there only one version of the pigpen key?
No. The version here, with A to I in the first grid, is the most common, but some people arrange the letters differently.
Can I print a pigpen message?
Yes. Press Save as picture to download your message as an image, then print it.
Is pigpen secure?
No. Each letter always has the same symbol, so it can be solved like any substitution cipher.