Inner Workings of the German Enigma

History of the Enigma• The concept was invented by a German named

Albert Scherbius in 1918• Scherbius tried to take the machine to the

German military but initially they weren’t interested

• A company called Gewerkschaft Securitas bought the patent in 1920 and started manufacturing the Enigma

• The German military became interested in 1925 in order to encrypt radio messages.

• The military made some enhancements.

What is the Enigma

• The Enigma is an Electro-Mechanical Device used to Encrypt Messages

• The Mechanical properties of the machine were based around gears that would turn as keys were pressed on the typewriter style keyboard

• The keyboard would also active electrical switches that would initiate an electrical current from a battery

Components of the Enigma

• Keyboard

• Plug Board

• Set of 3 Rotors

• Reflector

• Light Board

Enigma Keyboard

• Typewriter Style Keyboard – Used to enter the plaintext message into the machine.

Enigma Plug Board

• Plug Board – Used to make connections between letters of the alphabet. If a connection was made then the letters would be remapped to each other. If a connection was made between the letter “A” and “M” then “M” would get substituted for “A” and vise versa.

Enigma Rotors• Main Component of the Enigma• Flat disks with 26 electrical connections on one

face which correspond to the letters of the alphabet. The 26 electrical connections were mapped to 26 different connections on the opposite face of the rotor.

• Every rotor had a different mapping of the 26 connections

• Early Enigma machines used 3 rotors from a set of available rotors. Rotor move in an odometer fashion.

• Possible Alphabets 26x26x26=17,576• 3 rotors in 3 positions 3x2x1=6• Total Possible Alphabets: 17,576x6=105,456

Enigma Rotor Pictures

• Set of Rotors

• Rotor

• Disassembled Rotor

Enigma Reflector

• The Reflector was a component at the end of the array of rotors that would reflect the electrical current back through the rotors in the opposite direction and through a different route.

Enigma Light Board

• The Light Board was used to view the cipher text that was being produced by the machine.

How Does The Enigma Work

• There are a total of 9 permutations

• The key is the initial settings of the machine. Rotors used and in what slot, Plug Board, Etc.

Modern Day Enigma’s

• Java Based• http://www.ugrad.cs.jhu.edu/~russell/classes/enigma/

Modern Day Enigma’s

• Electronic (Enigma-E Machine)• http://www.xat.nl/enigma-e/

Conclusion

• The Enigma was revolutionary in its complexity but also in its ease of use.

• The efforts used by Governments to crack the Enigma are the basis for modern day cryptography.