Colossus computer
How the first programmable digital computer helped bring WWII to an end
The Colossus computer was a machine used by the British intelligence ser v ice during World War II to analyse and decr y pt telepr inter orders and messages enciphered with a Loren z SZ40/4 2 encr y ption machine by the Nazi Germany High Command. The contents of the messages were of incred ible value to the Allies, as they of ten contained key orders for German generals, including t roop movements and tactics.
Prior to the German use of the Loren z cipher, the Allies had successfully cracked their Enigma code and had for years held the abilit y to decode messages thanks to Alan Turing’s electromechanical Bombe machine. The Loren z cipher was much more complex, however, with the SZ40/4 2 encipher ing a message by combining its characters with a keystream of characters generated by 12 mechanical pinwheels. As such, w ithout knowing the key characters – ie the position of the pinwheels – no decr y ption could take place.