Jared Jones 

February 6, 2007 

CPSC-340A 

Dr. Bloss 

“Cracking the Enigma” -- Discussion Plan 

Cryptography 

• Why is it important? 

• What is its application today? 

• How can we relate modern cryptography to historic ciphers? 

• What are the pros and cons of cryptography? 

   

Introduction to Enigma 

• Enigma before Turing's analysis 

  • Methods of decrypting messages 

  • Problems with these methods 

• Steckered vs. Non-Steckered Enigma (A simple problem becoming more complex) 

• Sketch of Steckered/Non-Steckered Enigma Machines 

  • Various settings 

  • Inner wheels and tyres 

  • Rotational “turnover” description 

• Comic strip “paper enigma” 

Methods 

• Cribs – normally won't have the information required 

• FORTYWEEPYYWEEPY – infeasible for many Stecker 

• Bombe machines 

Turing's Contribution 

• Bombe 

  • Loops and chains 

  • Finding Steckered pairs 

  • US contribution to Bombe research (ULTRA) 

• Proposed additions to Bombe: Spider and Machine Gun (Diagonal tables and parallel analysis) 

Conclusion 

• How have the technologies present in the Enigma Machine and Turing's Bombe evolved? 

• How might Enigma and the Bombe machine inspired the development of Block Key Ciphers and Public Key encryption in the 1970s? 

Homework 

• Using the Paper Enigma Machine (http://mckoss.com/Crypto/Enigma.htm), try to solve as many of the Enigma Cipher Challenges (http://users.telenet.be/d.rijmenants/en/challenge.htm) as you can. These are very difficult and should give you some insight into the various methods of breaking Enigma-encoded messages before Alan Turing's contribution. Some of these may not require use of the paper enigma machine, as various clues are given.

Further Reading 

• Ellsbury, Graham. “The Turing Bombe: What it was and how it worked”. 1998. (http://www.ellsbury.com/bombe1.htm)

• Singh, Simon. The Code Book: how to make it, break it, hack it, crack it. March 2002: New York. Delacorte Press.

• Shaylor, Nik. “Enigma and the Turing Bombe”. 1997. (http://frode.home.cern.ch/frode/crypto/Shaylor/bombe.html)

• The Alan Turing Home Page. (http://www.turing.org.uk/turing/)

• The Turing Digital Archive. (http://www.turingarchive.org/)

• Turing, Dr. Alan M. Treatise on Enigma. September 1999. Frode Weierud's CryptoCellar. (http://f.home.cern.ch/f/frode/www/crypto/Turing/)

• Wikipedia Entry: Bombe. (http://en.wikipedia.org/Bombe)