Cryptanalysis of the Enigma Bletchley Park to describe the network that used the same Enigma setting sheets. Initially these were recorded using coloured pencils and were given the names "red", "light blue" etc., and later the names of birds such as "kestrel". During World War II the settings for most networks lasted for 24 hours, although towards the end of the war, some were changed more frequently. The sheets had columns specifying, for each day of the month, the rotors to be used and their positions, the ring positions and the plugboard connections. For security, the dates were in reverse chronological order down the
Cryptanalysis of the Enigma Knox (a veteran of World War I and the cryptanalytical activities of the Royal Navy's Room 40), worked on decipherment he had only the messages he generated himself to practice with. After Germany supplied modified commercial machines to the Nationalist side in the Spanish Civil War, and with the Italian Navy (who were also aiding the Nationalists) using a version of the commercial Enigma that did not have a plugboard, Britain could intercept the radio broadcast messages. In April 1937 Knox made his first decryption of an Enigma encryption using a technique that he called "buttoning up" to discover the