To fully understand the awesome device got to the wikipedia https://en.wikipedia.org/wiki/Jefferson_disk page I will try to explain it here to the best of my abillity.
President Thomas Jefferson is famous for being the person who wrote the declaration of independence, a founding father, and a politician. Well it turns out he was actually an inventor and mathematician(who knew right!).
A while back I visited the National cytological museum. For those who don’t know it is a relatively small museum next to the NSA headquarters buildings. It is about the history of cypher and encryption from the revolutionary war to around the cold war. One of the exhibits in the revolutionary war and civil war section was about this device. This is where I got the inspiration from.
What really impresses me about this device is that the concept is so simple yet deciphering it is so hard if not close too impossible. The way it works is you turn the disks so that they say on one line the message you want. Then you put the rod through the holes to keep the wheels from turning independently. Rotate all of the disks to a different line and right the message it says there on a piece of paper. So that when the recipient gets the message s/he will turn the disks to say that message on the page and will turn all the disks to where the message is. In the letter not in the code you should write the order of the disks and how many lines away the real message is from your message.
The genius behind this can be revealed when looking at other simple ciphers that were introduced before it. For example, if you write the simplest cypher where each letter is represented by another letter or symbol. One can easily crack it by finding words like ‘a,’ ‘all,’ or ‘I’. since if you found a word in the message you were trying to decode that said ‘WMM’ it is almost certainly ‘all’ then you could change all ‘w’s to ‘a’ and all ‘m’s to ‘l’s and so on. Obviously this is not a very good code. Whereas here a single letter can be different every time so a word like ‘all’ would not be recognized.
**The picture is of an earlier version that is why it only has eight disks. i haven't had a chance to print it yet but i will post when i have