Enigma Cipher

Overview

Students will make a papercraft version of the German Enigma machine to better understand how the encryption worked. Students will also look at the historical significance of Enigma and the people who worked to break the code.

Purpose

The German Enigma is one of the first examples of mechanization of cryptography. The operation of the machine was sophisticated but the mathematics of the combinations of the rotors, plugs, and starting positions created a code that the Germans believed was “unbreakable”

Objectives

Students will be able to:

• Encode/decode messages using the German Enigma
• Identify the historical context and important people in cracking the Enigma code.

Preparation

• Gather Pringles Cans
• Print, Laminate, Cut Enigma Strips
• Print copies of the Enigma Activity

Links

• For the Teacher
  • Enigma Pringles Can Description
  • Enigma Pringles Can PDF
  • Enigma Worksheet
  • Video on how to use Pringles Can Enigma
• For the Students
  • Enigma Rotor Details

    Vocabulary

Teaching Guide

Getting started:

German Enigma - Numberphile (video):

• https://www.youtube.com/watch?v=G2_Q9FoD-oQ

Activity:

• Explain the use and function of the Enigma Pringles can. - Print, laminate, cut enough enigma strips for each can. - The can itself can store the un-used rotors. - What is the “notch” point for each rotor? - Define the direction you will turn the rotor (I used “away” from the user.) - Depending on these uses, the messages may not work out perfectly. - Protocols need to be the same between messages to be able to successfully encode/decode.
• Decode and encode the messages in the worksheet.

  Activity:

  Create a Python version of the Enigma cipher.

• Use the existing files and create the missing rotors (4 & 5) as well as another reflector (b).
• Historical rotor settings can be found on Wikipedia
  • Enigma.py
  • Rotor1.py
  • Rotor2.py
  • Rotor3.py
  • ReflectorA.py

Wrap-up

Video - The flaw in the German Enigma:

• https://www.youtube.com/watch?v=V4V2bpZlqx8

Discussion:

• Why was it so important to have a strong encryption on messages during this era?
• Why was the German Enigma so difficult to break?
• Can we use standard tools like frequency analysis?

Assessment Questions

• Revisit the Vigenere Cipher, how was the Enigma different?
  • How was the Enigma similar to Vigenere?
• Knowing that enemies might have a version of the machine, why were the Germans still so confident in their design?

Extended Learning

Read: Chapter 3 - The Code Book

The Mechanization of Secrecy

After reading Chapter 3 of the Code Book, reflect on the use of the German Enigma during World War 2 and the work of Alan Turing and others to break the code. Again, this is a blog so I would like you to talk about it in a manner that explains the technology and it’s implications to an audience who does not know about it.

There are a few things I think you should look at in your blog:

• Prior military encryption
• Why was enigma better?
• Who tried to break it?
• Who was successful at breaking Enigma?
• How did they break Enigma?
• What were the implications of breaking Enigma while trying to keep that secret from the Germans? Please use photos and examples in your blog. This should be posted to your Wordpress blog.

3D Print an Enigma Cylinder

• https://www.thingiverse.com/thing:3555396/files

Watch Movie: Imitation Game

Standards Alignment

License

Cyber Security Curriculum is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.