The Kennesaw State University Department of Museums, Archives and Rare Books (MARB) presents exhibitions, public programs, collections, and educational services supporting KSU’s mission and encouraging dialogue about the past and its significance today. The Museum of History and Holocaust Education, as a unit of MARB, has developed a series of online modules, including this one, for university students to explore pivotal moments from the history of World War II and the Holocaust.
This online unit focuses on Allied efforts to break Axis codes and cyphers during World War II. The information obtained from decoded messages proved essential to battlefield success and, ultimately, an Allied victory. Using a selection of primary sources and secondary sources, this unit examines the importance of cryptography in World War II and the contributions of individuals to Allied decrypting efforts.
Title Image: Close up of a bombe. Courtesy Antoine Taveneaux
Image: Parallel Journeys exhibition at the Museum of History and Holocaust (MHHE). Courtesy MHHE
Essential Questions
Using the primary source material and content in this online unit, respond to the three essential questions found below. In your responses, include evidence from the content in this online unit. Please refer to the directions provided by your instructor on submitting your responses to these essential questions as well as to the questions posed throughout this unit.
- How did Code Talkers contribute to the Allied victory in World War II?
- What role did women play in World War II cryptography?
- How important was cryptography to achieving victory in World War II?
Image: WAVE cryptologist operating the U.S. Navy Cryptanalytic bombe, 1943. Courtesy National Cryptological Museum
Table of Contents
- Codebreaking in World War I
- The Enigma Machine
- Axis Efforts
- Bletchley Park
- Code Women
- Meet History Face to Face: Louvinia Jordan
- Meet History Face to Face: Alan Turing
- American Indian Code Talkers
- Meet History Face to Face: Chester Nez
- Using the Navajo Code
- Assessment
Code Breaking in World War I
At the start of the First World War, the intelligence communities that existed were, for the most part, weak and disorganized. While some domestic intelligence communities were strong, foreign intelligence was often neglected. Of the nations involved in World War I, Britain and Germany had the most developed and sophisticated intelligence communities.
World War I forced nations to rapidly develop modern, sophisticated intelligence systems and communities, and developments in cryptography were necessitated by advancements in battlefield communication, such as the telegram. Though substitution codes were the most common codes used during the war, the most important messages were encrypted in what were known as Trench Codes.
Encrypting messages added an extra layer of security to the coded message by applying a second mathematical code to it. Encrypting and decoding messages, however, required the use of codebooks. These codebooks proved to be a security liability because enemy soldiers could steal the books and decode encrypted messages.
U.S. forces proved very adept at the creation of Trench Codes, creating, printing, and distributing new codes every ten to fourteen days. This led to a series of military codes all named after various U.S. rivers, starting with the Potomac.
Though the most famous use of Native American languages in cryptography was the Navajo Code Talkers in World War II, code talking was pioneered by Cherokee and Choctaw soldiers in 1918. German forces found it very easy to decrypt codes written in English but had no exposure or experience with Native American languages. Therefore, orders could be relayed across battlefields between Native American soldiers in their native languages without the worry of them being intercepted.
Image: Portrayal of the World War I Choctaw Code Talkers by Choctaw artist, Gwen Coleman Lester, 2016. Courtesy Choctaw Nation
The Enigma Machine
Invented by a German engineer named Albert Scherbius shortly after World War I, the Enigma machine proved to be one of the most difficult encoding tools to crack over the course of World War II.
On its surface, the Enigma machine simply created substitution code. The complexity of the code lay in the mechanics of the machine, which ensured that the likelihood of a letter being substituted for the same letter twice was nearly impossible. The rotors and plug board in the Enigma machine created a polyalphabetic substitution code with trillions of possible permutations. Only by knowing the exact settings of the Enigma machine that sent a message could that message be deciphered.
If the Enigma machine had been used properly it would have been almost impossible to break. German secret services and civilian agencies who used the machine, however, did not employ proper procedures. These poor procedures allowed the Enigma machines to be reverse engineered and their codes cracked.
Watch the video below to see an Enigma machine in action and follow the link to an online Enigma machine simulator.
Image: Three rotor Enigma machine. Courtesy Imperial War Museum
This digital lesson was curated and designed by Amy Collerton from Georgia State University in collaboration with staff from the Museum of History and Holocaust Education at Kennesaw State University.