DIY spy: Make your own WWII Enigma Machine

You don't have to be a Bletchley Park alumnus or a wealthy WWII military collector to lay your hands on an Enigma machine. With some savvy technical skills and computer coding, you can make one yourself.

The Enigma machine was an intricate crypto device used primarily during World War II by Nazi Germany to send encoded messages to its military forces. Originally, Enigma machines were used by businessmen in the '20s who wanted to keep commercial messages secret. In 1923, the German Navy used its own Enigma machine and by the 1930s, it became standard equipment by the German Intelligence divisions.

In October 2013, a 1944 German Enigma machine was available for auction at Bonhams with an estimated worth of up to $82,000. At another auction in 2010, a 1939 Enigma machine fetched $110,900. Over 100,000 Enigma machines were made, but very few had the Enigma insignia.

If you don't have thousands of dollars to spare, you can make your own replica of an Enigma machine with this craft tutorial by ST-Geotronics on Instructables.

"This step-by-step guide will show you how to build a fully functional electronic replica of the world famous German Enigma Machine," ST-Geotronics wrote on Instructables. "This Arduino-based open-source project is able to encrypt and decrypt any Enigma M4 encoded message. Using multiplexing for the LEDs, this circuit with 115 light-emitting diodes uses only 38 pins, and the 36 push buttons use only 4 pins total, thanks to properly placed resistors (and the P-Channel MOSFETs) in the keyboard loop."

The machines used by the military in Nazi Germany were of most interest to the legendary code breakers at Bletchley Park who would crack the Enigma codes and end up shortening WWII by two years.

According to Bonhams auction house, "Proudly named 'The Enigma Machine,' one might think that there was only one type of machine that was used to send encoded German messages during World War II. But that's not the case. There were many members in the Enigma family, and as the war went on, more and more complex methods and additions were made to the machines to make cracking their codes even more difficult for the crafty code breakers at Bletchley Park."

The basic design of the original German military Enigma machine includes a keyboard; a set of rotating wheel disks called rotors, which each contained the letters of the alphabet; a plugboard; and a lampboard.

According to this handy guide by "Nova":

In choosing a basic setup for the machine, there was a choice from the 60 possible wheel orders, the 17,576 ring settings for each wheel order, and over 150 million stecker-pairings (allowing for six self-steckered letters). So the total number of daily possible keys was about 159 million. In each of these configurations, the machine had a period of 16,900 (26x25x26) keyings before the mechanism returned to its original position. But there were weak points. The Enigma is simply a swapping machine of an advanced type. All Enigmas of the same model, set up in the same way, will produce identical swaps. In any position where keying B gives T, keying T will give B. And keying B can never give B.

The tutorial is extremely detailed, requiring multiple bits and bobs and including special software code and Circuit Schematics.

But for those Enigma collectors who can't be bothered to make their replicas from scratch, ST-Geotronics also offers custom-made Enigma machine replicas and kits on their Web site.

To further understand how secret messages were sent, watch this video on cracking the Enigma Machine code.