Crypto and the War to End All Wars: 1914–1919

The use of wireless telegraphyWireless telegraphy—radioRadio—during World War I marked the advent of modern cryptology. For the first time, commanders were sending enciphered messages to front line troops and for the first time, the enemy had an enormous amount of ciphertext to work with. This spurred the development of more complicated codes and ciphers and eventually led to the development of machine cryptography. World War I is the first time that the Americans had a formal cryptanalytic organization. It is the beginning, in all the nations involved in the conflict, of the bureaucracy of secrecy. In the United States it marks the first appearance of the two founding fathers of modern American cryptology, Herbert O. YardleyYardley, H.O. and William F. Friedman. This chapter introduces Herbert Yardley and William Friedman and examines some of the cryptographic systems used during World War I.