Fully functioning 1935 Enigma I machine used by the German military
Early, fully operational three-rotor Enigma I electromechanical cipher machine made for the German military by Heimsoeth und Rinke, Berlin, in 1935, during the build up of the German forces in violation of the Treaty of Versailles prior to World War II. Based on the chassis of the commercial Enigma D, the Enigma I machine was the standard Enigma machine used by the German military throughout the war. It features an ebonite Steckerbrett [plugboard] on the front, which was exclusive to the German armed forces and exponentially increased the complexity of the code. This version of the Enigma is sometimes referred to as the Heeres [Army] Enigma, Wehrmacht Enigma, or Luftwaffe Enigma due to its military-specific application. This particular example boasts rare characteristics found only on early production machines: metal extra Stecker cable holders in the lid, rotors with all-metal construction, and original metal badges and tags. This early production Enigma machine saw service with the German military both before and after the outbreak of World War II in 1939.
The Enigma machine is housed in its original stained oak case with hinged lid and hinged front panel, with serial number plate "A 3995" inside the lid. Also inside the lid are a metal stamped "Enigma" label, manufacturer's plate, two spare Stecker cables, 10 light bulbs, contrast screen, and original "Zur Beachtung" instructions for cleaning, use, and troubleshooting. The inner front panel is stamped "Klappe Schliessen" and the case retains its brown leather carrying handle on the back.
The three included rotors—marked as "I," "IV," and "V"—are also marked with matching "A 3995" serial numbers, a rarity as the few surviving Enigmas have often been reassembled from disparate parts. When the machine was issued in 1935, it would have had three rotors marked "I," "II," and "III"; beginning in 1937, Enigma machines were issued with five rotors in order to increase their cryptographic security. Those machines already in use by the military—like this one—were issued rotors "IV" and "V" with matching serial numbers. The three rotors present are of all-metal construction typical of only very early pre-war Enigmas. When resources became scarce as World War II progressed, Bakelite was used for the rotors' thumbwheels as well as the Stecker cable holders. Each rotor can display one of its 26 numerals through the three windows in the machine's cover. They have spring-loaded brass contacts on the sides corresponding to each of the 26 numbers and they may be arranged in any order on the internal shaft. The specific settings of the rotors and plugboard were determined on a daily basis via a secret codebook that allowed the German forces to synchronize their Enigma machines.
The Enigma machine has a standard German "QWERTZ" keyboard with 26 white-on-black keys, with matching "QWERTZ" lighted display. When a key is pressed, the corresponding encoded letter—as determined by the specific arrangement of the rotor wheels and plugboard—is illuminated. The rightmost rotor steps once each time a key is pressed. At an adjustable point it triggers the middle rotor to step and so on. Through this mechanism, an easily crackable simple substitution cipher is avoided—letters are not encoded the same way twice. An encoded message would be written down and transmitted, usually via radio telegraph (a standard World War II-era German Wehrmacht Baumuster T1 telegraph key is included with this machine). In order to decode a message, the Enigma machine on the receiving end would have to be set up with the plugboard and rotor wheels in the same pattern as the sending Enigma*: when the encoded message was typed in, the decoded letters would light up, revealing the secret message one character at a time. Since no original batteries have survived, this machine has been modified to accept two modern D batteries as a power source in order to allow it to function.
First patented in 1918 by Arthur Scherbius, the Enigma machine was developed for use in the transmission of confidential information: in addition to its obvious military and diplomatic applications, the machine found commercial use for the encryption of sensitive financial data. The German military adopted the Enigma as its primary cipher in 1926, after learning that the British had intercepted and interpreted coded German naval messages during World War I. During the subsequent buildup of German forces, Poland felt particularly vulnerable—having been ceded disputed border territories by the Treaty of Versailles—and sought to crack the Enigma. Genius Polish codebreakers—led by Marian Rejewski, Jerzy Rozycki, and Henryk Zygalski—developed techniques for the decryption of Enigma code, and turned over their research to Allied counterparts after Germany's 1939 invasion of Poland. Alan Turing and the other brilliant code breakers at Bletchley Park continued their important work, speeding up the time it took to decode Enigma messages. The code breaking efforts at Bletchley Park led to the development of the world's first computers as technology was pushed to defeat German cipher machines. Historians agree that these decoded messages shortened World War II by about two years, perhaps denying Nazi Germany the time needed to develop nuclear weapons. As a fully functioning, early example of the German military's Enigma machine, this piece is truly a marvel of technological and WWII history.