Pigpen

The pigpen cipher (sometimes called the masonic cipher or Freemason's cipher) is a simple substitution cipher exchanging letters for symbols based on a grid.
This cipher goes back to the time of the Crusades (1095-1272) but it wasn’t until the time of the American Civil War in the 1860s that the pigpen cipher became popular for sending secret messages. This cipher is known as the pigpen cipher because the letters of the alphabet – the “pigs” are trapped within the lines – the “pens.” The shapes made by these “pens” either with or without a dot, represent the letters inside.
Other Diagram Ciphers
Tic-Tac-Toe Cipher

Take a look at the tic-tac-toe symbol below and you’ll see that the entire alphabet is contained in its nine different spaces or “rooms” with a question mark added after the letter Z.We

can represent each letter by drawing a picture of the room it is in and by indicating with a dot whether the letter is at the top, middle or bottom of its room.



Triple Square Cipher

This cipher uses a combination of triangle and dots. Although the key is drawn large so all the letters can fit, when you send a secret message you can draw all the triangles the same size.

The orientation of the triangle and the placement of the dot inside will tell your friend what letter is needed to decipher your secret message.

Quarter Circle Cipher

The quarter circle cipher uses little pie shapes and dots as a substitution for letters. A quarter circle and a dot in one of seven possible positions, three around the outside and four inside, represent each letter of the alphabet.