Cypher Wheel

A Cypher Wheel is a wooden item that is made up of two wooden disks, one of which is smaller than the other placed on top of the larger disk. Around the circumference of both disks are the letters from A to Z. Turning either of the two wheels changes the combinations these can then be used to encode messages so that without the right combination the message is not useful.
The messages themselves are transmitted from city to city by the use of telegraph along copper wires that are buried. At the scale within cities, messages are carried by messenger. This is to save on copper and for citizens to have employment.

History

The Cypher Wheel was once used as a toy by older children in The Old World. In The New World, they are used by government officials to encode messages between cities. All cities have a codebook that details not just their own code setting but others for other cities.

Deciphering A Message

1. -... -.. .-. / -... .-. - / .-- . / .... .- ...- . / ... . -. - / .- / - .-. .- .. -. / -.-- --- ..- .-. / .-- .- -.-- / .-- .. - .... / ... ..- .--. .--. .-.. .. . ... / -.-- --- ..- / .-. . --.- ..- .. .-. . -..

   — The Original Telegraph Message Sent 23rd March 2121

   
   At this point, the main aim is to change the morse code into plain English.



2. BDR BRT ucfytcqclryrpyglwmspuywugrfqsrrjgcqwmspcosgpcf

   — The Telegraph Message Translated from Morse Code to Plain English.

   
   After the message has been translated from Morse to Plain English. The starting six letters describe where the message is going and where it is coming from. The first three letters are where the message comes from. In all cases, the decryption code is at the first three letters, BDR is Birdencaster, so looking up Birdencaster in the codebook gives the cypher to decrypt the message.
   The decryption code for Birdencaster Is to set both wheels so that both “A”s match. After that the next step is to look at the date and for the description key do the same for the cypher wheel. For example the deception key is left, right over and over until the date ends. Since the date the message was sent 23rd March 2121 the user of the cypher wheel would do this with the outer wheel of the 2 left, 3 right, 0 left, 3 right, 2 left, 1 right, 2 left and 1 right.



3. 

   The 23rd March 2021 Setting by computerscienced.co.uk

   The correctly set cypher wheel would look like ^{[image Above]}. The Last step is to match the letters. The coded letter is the outer wheel while the inner wheel is the correct letter.



4. BDR BRT we have sent a train your way with supplies you required

   — The Decrypted Message

   
   The Resulting Message becomes apparent. Bristol should expect a train to come that has come from Birdencaster.

The Power Of The Codes and How To Defeat Them

The powerful part is twofold. Firstly, this code does not share the same starting step so not all codes start AA at the beginning but rather other combinations as well as changing which wheel needs to move or the steps needed to get to the correct end step. Secondly, the encryption of the message to other cities is impressive with a simple system.
Of course, there are some limitations such as gaining access to the codebook, cypher wheels and wiretapping to get the message then, the person that should not have access to this information does.

Item Type
Communication

Article Contents

Further Resources

This article was inspired by a Project 863 video: Link
Plain English to Morse Code
Cypher Wheel Maker

Acknowledgements

AmelieIS
AmelieIS’s World Anvil Author Page