Excerpt from The PC Pioneers
The UK Government Code & Cipher School at Bletchley Park was established on this day in 1939.
Alan Turing became head of Hut 8 at the Government Code & Cipher School at Bletchley Park, where cryptologists were charged with putting Turing’s theoretical thinking into practice on the decoding of German naval encrypted signals.
Before the war the Poles had captured a German Enigma machine and crypto-analysts had developed an electromechanical machine to decode the German field and theatre messages; it was named the Bomba.
The Enigma codes scrambled messages using a three or four stepping rotor system. Enigma sent its messages in Morse code which it could scramble in 150,000,000,000,000,000,000 different ways!
In 1941 a somewhat more complex system was detected being used for high-level messages by the German High Command. Enigma interceptions identified that the Germans called these teleprinter system messages Sägefisch or sawfish. The messages were therefore codenamed by the Allies as ‘Fish’. Material they had decoded from the Enigma also indicated the equipment used was named a Geheimschreiber or secret writer.
The task of designing the first of these systems for the Germans had been given to the Lorenz Company which came up with the SZ 40/42 machine; called Tunny by the Allies. This system used teleprinters and their 32-character Baudot code; this was the code used by the telegraph system before ASCII was developed.