Friedmann.hu.txt -

William F. Friedman, recognized as the father of modern American cryptology, pioneered the application of scientific, statistical methods to breaking codes and ciphers [1, 2]. His foundational work includes the development of military cryptanalysis training materials and leading the team that broke the Japanese "PURPLE" cipher machine [2, 3]. As the primary figure in establishing U.S. Army cryptographic security, his legacy continues through the foundational methodologies of the National Security Agency [4]. Further details regarding his impact can be explored through declassified documents on the National Security Agency's official website.