Elizebeth Smith Friedman William Friedman Frank Rowlett Abraham Sinkov Genevieve Grotjan Feinstein Leo Rosen Joseph Rochefort, leader of the effort to crack Japanese Naval codes Joseph Mauborgne Agnes Meyer Driscoll SIGABA cipher machine SIGSALY voice encryption SIGTOT one-time tape system M-209 cipher machine Station HYPO cryptanalysis group Station CAST cryptanalysis group Station NEGAT See also Cryptography History of cryptography World War I cryptography Ultra (cryptography) Magic (cryptography) Cryptanalysis of the Enigma Bombe Enigma (machine) SIGABA TypeX Lorenz cipher Geheimfernschreiber Codetalkers PURPLE SIGSALY JN-25 Bletchley Park Biuro Szyfrów PC Bruno SIS US Army, later moved to Arlington Hall OP-20-G US Navy Marian Rejewski Jerzy Różycki Henryk Zygalski Alan Turing W. T. Tutte John Tiltman Max Newman Tommy Flowers I. J. Good William Friedman Frank Rowlett Abraham Sinkov Joseph Rochefort Agnes Meyer Driscoll Hans-Thilo Schmidt References History of cryptography Cryptography