Jefferson Cylinder

Use the cylinder to send your name in code. Use the wheels to spell you name and use the line underneath as the code.

Use the cylinder to decode the message CZOOLEZLOP. What does it say?

The wheels can be removed and rearranged. How many ways are there to arrange the ten wheels?

The Jefferson cylinder uses ten wheels, with different mixed-up alphabets. You can then send messages, in blocks of ten letters, with each letter using a different code. This is a very good idea because it helps to hide the frequencies of the letters, which is a common method of breaking codes. Unfortunately, this does mean that every tenth letter is sent with the same cipher. If a code breaker can work that out, then they can use frequency analysis on every tenth letter to break the code. A code that uses more than one cipher is called a polyalphabetic cipher. If the sequence of ciphers is long enough, then this can be a very difficult code to break. This idea was later used in the Enigma machine where each letter of the message was sent with a different cipher.