The Black Chamber and Codebreaking in the 1920s

What was the primary function of the Black Chamber in the 1920s?

• To create business codes

• To break military codes

• To design encryption machines

• To train codebreakers

Who led the Black Chamber and was known for his codebreaking skills during World War I?

• Alan Turing

• William Friedman

• Herbert O. Yardley

• Craig Bower

During the 1921 Arms Control Conference, what was the United States' main objective with Japan?

• To establish trade agreements

• To limit Japan's naval size

• To share codebreaking techniques

• To form a military alliance

What method did the Black Chamber use to intercept Japanese communications?

• Undercover agents

• Carrier pigeons

• Telegraph companies

• Radio signals

What key insight helped Yardley break Japan's diplomatic code?

• The time of message transmission

• The length of the messages

• The repetition of letter pairs

• The use of a specific cipher machine