Search our Website

Visit to National Crytologic Museum - Axis Exhibits

« Allies exhibits

1. SZ40 (Tunny)

Nicknamed the Tunny by the British, the German Army used the SZ40, for high-level communications. It provided on-line encryption and decryption of messages and could handle large volumes of traffic at high speed.

The Tunny depended on wheels for its encryption/decryption and generated Baudot Code used in normal telegraphic transmissions.

2. Siemens T-52 (Sturgeon)

The German Air Force began using the Siemens T-52 in 1941. Nicknamed the Sturgeon by the British, it provided the German military with on-line encryption/decryption and supported a teleprinter. Ten wired rotors were used for the encryption. They allowed for 893 quadrillion (892 followed by 15 zeros!) possible set-ups on one wheel order. The key list indicated five of the positions. The operator selected the other five settings.

3, 4. German Army Enigma Machine

The Enigma cipher machine was portable, durable and self-contained. Germans on the front line relied on it for enciphering tactical messages. However, the Enigma machine required two to three operators to function effectively: one operator to encipher, one to read the results, and a third to copy down the enciphered message.

Tthe prevailing feeling by the German armed forces was that messages enciphered on the Enigma would never be broken because the time needed to do so would be prohibitive. This proved to be untrue.

5. German Air Force Enigma

Like the army, the German Air Force relied on the Enigma machine for secure communications. However, radio interception and timely cryptanalysis by the British, revealed plans such as those for the decisive air attacks known in the Battle for Britain, well in advance of the strikes. The losses suffered by the German Air Force during this time were never regained.

6. Die Kriegsmarine (Navy)

The German naval force relied heavily on radio communications. Each naval vessel was issued an Enigma cipher machine to ensure secure communications. However, as with other the services, the dependence upon Enigma for communications security proved to be disastrous.

7. G Enigma

The G Enigma was a specially constructed cipher machine given to some foreign governments which were friendly to Germany. Two hundred G Enigmas were issued to the German Army High Command (OKW) for an unknown special purpose.

8.The Enigma Circuitry

Pressing one of the keys of the enigma caused an electrical current to pass through the machine until it reached a light, which served as the machine's readout.

As a text character passed through the plugboard and rotors, the value continually changed until it reached the light, which indicated the final cipher character. The process was reversed for deciphering. Notice that there are no number keys on the machine. All numbers were spelled out as words.

9, 10. The Stecker plugboard

A plugboard (Stecker in German) was added to military Enigmas to enhance their security. The use of the plugboard board before encryption allowed the operator to manually change the value of any character.

The use of ten cords was optimum.  When combined with Enigma's other features, the plugboard added 150 billion variations to the possible cipher value of any character.
Because the Stecker combinations were manually set, they were unpredictable.


11, 12, 13. The Enigma's rotors

To further enhance Enigma's security, the German military issued extra rotors with each machine – two for Army and Air Force machines, and four for Navy. Each rotor was wired differently and identified with a Roman numeral. Rotors were selected for the day and placed in the machine in the proper left-to-right order.

14. Enigma Uhr

The Uhr (clock) was a German mechanical device used to further increase the security of the Enigma.

When the clock plugs were substituted for the original ones in the Enigma plugboard, the electrical current was directed through the clock. The Enigma operator could select 40 different plugging arrangements by turning the large knob on the clock.

15, 16. T Enigma and Japanese Enigma

The T Enigma was a specially wired German commercial type machine. Five hundred of these Enigmas were given to the Japanese Navy for joint communications.

The Japanese machine on display is an "Enigma" type rotor cipher machine. Note Japanese katakana syllabary.

17, 18. Japanese Navy Red Machine

The Japanese Navy Red Machine on dispaly was captured by the U.S. Navy. The machine separated the alphabet into two subgroups, but instead of using the Romanized spellings, it has a katakana keyboard. It is believed that due to the difficulty in using and maintaining the machine, it saw little use by the Japanese Fleet.

19. Jade

The Japanese Type-97 cipher machine was known to the American cryptanalysts as Jade and was one of the three varieties of Japanese machines that used a series of telephone selector switches to encipher/decipher top-level messages.

Top secret messages enciphered by the Jade, Coral, and Purple machines and transmitted by radio, were intercepted and decrypted by American Army and Navy Intelligence personnel. The information gained by this source was of the highest level of importance and was instrumental in the Allied victory in the Pacific. This Jade machine was captured in Saipan in June 1944.

20. Purple

This is the largest of three surviving pieces of Baron Oshima Hiroshi's cipher machine, code named Purple by the U.S. Army's Signal Intelligence Service. It was recovered from the wreckage of the Japanese Embassy in Berlin in 1945. Although no Purple cipher machine was ever captured intact, it is believed that Purple looked very much like Jade.

Information on this page is based on signs and other information at the National Crypologic museum in Annapolis Junction, MD.