Questions?
The Enigma Cipher
Use
What do you know about how to use Enigma now? What does it take to set up an Enigma machine to encrypt or decrypt?
Rotors: put desired rotors in desired order and turn them to desired position, then use the same order & starting position to decrypt.
Each rotor also has a ring setting, which affects how positions are identified and when the neighboring rotor advances. So part of setting up is setting the desired ring settings.
Finally, there’s a plugboard that swaps certain pairs of letters as they enter and leave the rotors. Setting up includes inserting cables to make the desired swaps.
So an Enigma key consists of...
- The rotors to use and their order
- The ring settings and initial positions of each rotor
- The plugboard connections
- Which reflector to use (not something we talked explicitly about in class).
Simulators
See either http://enigma.louisedade.co.uk/enigma.html or https://cryptii.com/pipes/enigma-machine
Practice
Make sure you can encrypt and decrypt messages for yourself.
Send / Receive
Encrypt a message, give it and your settings to someone else, and be sure they can decrypt it.
Key Exchange
How do you communicate your settings to another group when “hostile” parties in between want to intercept that information?
Next
Summarizing and quoting others’ work.
Read They Say, I Say chapters 2 and 3.