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 defined somewhat differently in that era than in modern cryptography. First, there is the "identification" of the system in use, in this case Enigma; second, "breaking" the system by establishing exactly how encryption takes place, and third, "solving", which involves finding the way that the machine was set up for an individual message, "i.e." the "message key". Today, it is often assumed that an attacker knows how the encipherment process works (see Kerckhoffs's principle) and "breaking" is often used for "solving" a key. Enigma machines, however, had so many potential internal wiring states that reconstructing the machine, independent of particular