Alan Turing is Da Bombe: Alan Turing is Da Bombe Anna Reetz Krissi Lum


Early Life: Early Life Alan Mathison Turing was born on June 23rd, 1912 in Paddington London. He lived with family in England for most of his life while his parents lived in India. At a young age he started showing an interest in the sciences.


Education: Education Attended the Sherborne School in Dorset. Attended King’s College in Cambridge in October of 1931 to study mathematics. He spent most of his time there researching probability theory. His research led him to become a Fellow of King’s in 1936. He came up with a theory that stated that all automatic computations could not solve all problems Attended Princeton to get his PhD in mathematical logic under the direction of Alonzo Church


Christopher Morcom: Christopher Morcom Turing was not a very successful student until he met Christopher Morcom Morcom provided Turing companionship and competition. Unfortunately Morcom died in February of 1930. After his death Turing vowed to continue researching Morcom’s ideas of the mind. Befriending Morcom sparked Turing’s interest in artificial intelligence.


Alonzo Church: Alonzo Church While Turing was studying probability an American mathematician named Alonzo Church was also studying the same thing. Church recommended Turing’s paper for publication. Together they developed the Church-Turing thesis which states that any effective calculable function can be calculated by a universal Turing machine. Church took Turing under his wing to study at Princeton.


Pre-Bletchley and Bletchley Park Work: Pre-Bletchley and Bletchley Park Work After Princeton he went back to England to finish his Fellowship at King’s in the summer of 1938. When the war broke out with Germany in September 1939 he left King’s to work for the British cryptanalytic department. While at Bletchley he succeeded in breaking the fish and enigma code.


How’d He Do It???: How’d He Do It??? Turing broke Enigma by creating a mini computer called a “bombe” He built it using research by Polish mathematicians. He received the Order of the British Empire for his work at Bletchley Park


Enigma Explained: Enigma Explained The Enigma was built by Arthur Scherbuis and E. Richard Ritter. They first proposed Enigma to the German Navy and the Foreign Office but were turned down. They then brought their idea to Gewerkschaft Securitas who founded the CAG. Soon the CAG began publicizing and marketing the Enigma Model This model incorporated a typewriter but lacked the reflector. This was an extremely complex machine.


The Reflector: The Reflector Was suggested by Willi Korn This allowed for models to be lighter and harder to break It made it so that encryption and decryption were the same process. It also made it so that no letter could ever be encrypted as itself. The first reflector could be inserted into one of two positions while the second could be set into 26 different ones. The reflector never moved during encryption but could be set in a different position each time the encryption was being changed.


The Rotors: The Rotors The rotors were about 10 cm in diameter and had a series of brass spring loaded pins on one side and a correspond number of electrical contacts on the other. There were 26 pins and electrical contacts, each one of these represented a letter of the alphabet. When the pins of one rotor touch the electrical contacts of the next one an electrical current was passed through. One rotor creates a simple substitution cipher which is monoalphabetic. But the Enigma had more than one rotor, so therefore it was polyalphabetic. An Enigma machine with 3 rotors has 17,576 possibilities.


The Stepping Sequence: The Stepping Sequence This makes the rotors even more complicated and harder to break. They used a ratchet and a pawl to make this possible. On the edge of each rotor (the ratchet) there are 26 teeth that correspond to each of the 26 letters. The pawls are then attached to the machine itself and engage the teeth on the ratchet.


The Plug Board: The Plug Board This is what made the Enigma so hard to break. The plug board was attached on the front of the machine facing the user. Without this plug board the Enigma could have been broken using hand methods. In order to use the plug board you needed cables that connected the letters to each other. The idea is that with the plug board you can connect two letters and switch their currents so that it changes the substitution cipher even more.


Ay, Ay, “Bomba”: Ay, Ay, “Bomba” The English were not actually the first ones to break the Enigma code. A man by Marian Rejewski was the first to break Enigma. He created a machine called a “bomba”. Worked until the Germans added things to make it more complicated to solve


The “Bombe”: The “Bombe” Along with Gordan Welchman, Turing created a mini computer called the “bombe”. It could not decipher Enigma itself. The “bombe” is a set of rotors with all the same wire settings as Enigma but it’s designed to be spun by a motor that will step through all the possible motor settings. It is believed that the invention of the “bombe” shortened the war by two years.


End of His Life: End of His Life Turing spent the end of his life working on theories of Artificial Intelligence. Using the Ferranti Mark I computer he attempted to examine and model works of biological growth. In 1952 Turing was exposed as a homosexual and was sentenced to getting shots of oestrogen to reduce his libido On June 7th, 1952 Turing was discovered dead with a cyanide kit set up in another room. He committed suicide by eating an apple laced with cyanide. He was 40 years old.