History & Culture

World War II codes, ciphers, and code breakers

Let’s talk about World War II codes and code breakers. In our previous article, we mentioned the Enigma machine. The German Enigma machine is the most famous example of a series of electro-mechanical rotational encoding devices used by the powers in World War II. The British used a similar machine called Type X, while Americans developed a more complex encryption machine, SIGABA. The Japanese encryption machine was producing a code called PURPLE, which code was broken in 1942. The encrypted code produced by all these machines was assumed to be unbreakable. Because it was requiring an enormous number of calculations to break an encryption system that is sending new signals every day, every hour or even every minute.

Code names of World War II, cipher machines, and code breakers

However, often a crack would appear in the armor and it was a result of human error or laziness. The story of how Enigma was broken, which we will tell in another article, also points to similar problems. The intelligence received by deciphering the Enigma code was called ULTRA, and just as in the Zimmermann Telegram, the issue of ULTRA intelligence was how far it could go without noticing the Germans that their secret codes were deciphered and read.

  • Type X Mark III
Type X Mark III World War II codes and code breakers
Type X Mark III

Designed for field use, this code breaker works manually and does not require electrical energy. The tape roll is being changed according to the unencrypted or encrypted message, and the hand lever turned the rotating cipher discs.

World War II codes and code breakers SIGABA

This code breaker which was more complex compared to Type X has provided messaging with the Combined Cipher Machine (CCM) system since 1943. The machine was too heavy to be used in the field. The encryption used three sets of five coded rotor discs, but no reflectors.

Bletchley Park and women code breakers

Female code breakers in the Second World War.
Female code breakers in the Second World War.

This courthouse in Buckinghamshire, England, was the venue for the struggle to break the Enigma encryption system, among all other things. In 1939, it became the headquarters of the Government Code and Cypher School, which was newly established and became the new British decryption center, replacing Room 40. With the war, it was filled with a strange group of cryptographers (or cryptanalysis), mathematicians, scientists, historians, linguists, and scientific researchers. A staff of carefully inspected army printers, secretaries and communications officers supported the group. Rounders and tennis matches were held to encourage creative collaboration. The team’s only difficult task was not Enigma, they also worked on the German Navy’s hand codes, and the other codes sent by the Italians and the Japanese.

Code names of the Manhattan Project

Manhattan Project

The most important and secret initiative in the war was the development of a nuclear “device” as soon as possible. A new project called “Manhattan” was undertaken by the USA with the support of the UK and conducted by a multinational group under the supervision of American physic genius J. Robert Oppenheimer. This name was derived from the U.S. Army Corps of Engineers in the Manhattan Engineers District of New York City. The code names for this top-secret project, operated in the state of New Mexico, in the territory of the Sangre de Cristo mountains, were:

  • 509th Composite Group

Using the B-29 Superfortress aircraft, this group was the bomber wing of the Manhattan Project.

  • Alberta

The crew assembling the bombs on Tinian Island in the Pacific.

  • Alsos

Secret Allied missions operated in Europe’s occupied areas to hijack nuclear scientists and raw materials such as uranium. There were only three.

  • Bockscar

Aircraft dropping the atomic bomb on Nagasaki on August 9, 1945.

  • Box 1663

The Santa Fe postal code used by everyone involved in the project.

  • Enola Gay

Aircraft dropping the first atomic bomb on Hiroshima on August 6, 1945. It was named after the mother of Pilot Lieutenant Paul Tibbets.

  • Fat man

The atomic bomb detonated on Nagasaki on August 9, 1945.

  • Fission

This term found by Otto Frisch means separating atoms via neutron bombardment.

  • Gadgets

A term used by Los Alamos officials for nuclear devices that they have developed in general; “Small tools”…

  • Little boy

The atomic bomb dropped on Hiroshima on August 6, 1945.

  • Site-Y

Los Alamos laboratory. The inhabitants of the region called here as “peak”.

  • Trinity

Location of the first nuclear test on July 16, 1945.

Code names of World War 2 operations


Most forces participating in the Second World War found a code name for almost any operation or initiative to provide a superficial level of security.

  • Adlertag

Luftwaffe attack leading to the Battle of Britain, 1940

  • Attila

The occupation of the Vichy region of France by the Nazis, 1942

  • August storm

Manchuria’s invasion by the Soviet Union, 1945

  • Avalanche

Allies’ landing in Salerno, 1943

  • Avonmouth

The Allied operation to Narvik, 1940

  • Bagration

Soviet offensive aimed at liberating Belarus, 1944

  • Barbarossa

The German attack on the Soviet Union, 1941

  • Cartwheel

Combined allied operations in the Southwest Pacific, 1943

  • Gomorrah

The bombing of the British Air Force against Hamburg, 1943

  • Ichi-Go

Japanese Offensive in China, 1944

  • I-Go

Japan’s counterattack in the Southwest Pacific, 1943

  • Lightfoot

Battle of El Alamein, 1942

  • Market-Garden

The Allied landing near Arnhem, 1944

  • Nordlicht

German Offensive to Leningrad, 1942

  • Overlord

The Allied invasion of Normandy, 1944

  • Steinbock

German airstrikes against English cities, 1944

  • Torch

The Allied landing on French North Africa, 1942

  • Weiss

Polish invasion of Germany, 1939