Alan Mathison Turing Article A Man of Machines The world celebrates the hundredth anniversary of Alan Feature Feature Turing who laid the foundation for the ‘intelligent machine’ MANAS PRATIM DAS T is extremely unlikely that Adolf Hitler knew about a British mathematician Icalled Alan Mathison Turing but had Hitler somehow known the fellow he could Dip the apples in the brew, have identified one more factor that led Let the sleeping death seep to his downfall. War historians might scoff through… at giving too much importance to an Alan Mathison Turing individual in deciding the outcome of the committed suicide on 8 June Second World War. 1954. His body was discovered But they would be uncomfortable in with an apple lying half- ignoring the role Turing played in cracking eaten beside his bed. the codes created by the mighty German Enigma machine. Surely, breaking the Enigma code is not the only contribution that Turing made in his lifetime but it was This course and the associated stream that it had set superior standards in certainly the most important from the of events finally led him to Bletchley Park. encipherment. historical viewpoint. Whatever it meant to lay citizens, Bletchley Alan Turing returned from America to Park, after the autumn of 1939, had The Machine his homeland England in the fall of 1938 become the address of Britain’s core At the end of the First World War the after having turned down an offer to work group of codebreakers. The German decimation of Germany began through as John von Neumann’s assistant at blitzkrieg that was conquering countries at the Treaty of Versailles. It was an unjust and Princeton. In June of that year he had a very fast rate had to be thwarted. The highly biased treaty where the victorious earned his PhD with a groundbreaking Allies, of which Britain was a part, knew that Allies put all the blame on Germany and dissertation titled Systems of Logic Based their best bet lay in cracking the secret made it pay heavily for the damages. But on Ordinals. German code that was making German deep inside the German psyche there Back home, he was recruited to join military progress possible. remained an anguish and zeal to avenge a course on cryptography and Communicating through secret this injustice. The Enigma machine can be encipherment sponsored by the ciphers or codes had been in vogue since thought of as being a product of this Government Code and Cipher School in time immemorial. Every major user had mentality. London. The school’s director Alastair tried to make his code more complex so Electrical Engineer Arthur Scherbius Denniston had heard about Turing’s that it became unbreakable. But in every designed this machine to replace the exceptional mathematical ability and was age a solution had somehow sprung up. inefficient systems of cryptography used keen on having him among his students. And therefore, no code had been in the First World War. It will be wrong to Turing understood the need and was willing absolutely secure. The Enigma code did term his effort as ‘all patriotism’ and ‘no to help. succumb to this age-old rule but before profit seeking’ because he had made all 31 SCIENCE REPORTER, APRIL 2012 Feature Article Breaking the Enigma code is not the only contribution that Turing made in his lifetime but it was A slate statue of Alan Turing with the famous Enigma machine certainly the most important from the historical viewpoint. necessary arrangements to rake in profit As Simon Singh puts it in his bestseller set up a secret bureau mainly with the aim through the sale of his innovation. He The Code Book, “Over the next two of cracking Enigma codes. The genius founded a company with his friend Richard decades, the German military would buy who led the mission was called Marian Ritter and took out a patent for his over thirty thousand Enigma machines. Rejewski. machine. Scherbius’ invention provided the most Over the years Rejewski built up an It was a formidable cipher machine secure system of cryptography in the elaborate system to decipher Enigma that combined electrical and mechanical world, and at the outbreak of the Second codes. His major achievement lay in parts. However, the person in charge of World War the German military’s discovering the method for finding the key encrypting a plain text message for communications were protected by an for encipherment. The Germans changed onward transmission was not required to unparalleled level of encryption”. the key everyday or even sometimes once know the structural intricacies of the in a few hours and it was the heart of machine. He could just type the text on Attempting A Break encipherment. Rejewski kept pace with the the keyboard of the machine and receive Germany’s neighbours and its adversaries German military as they made changes a jumbled collection of letters in return. could not sit idle and watch Germany’s to the machine in order to make the That was the coded message. The receiver, secret communications go from strength encoding a more complex process. in turn, had to type the apparently to strength. They had to do something in By 1938, the Poles were at the peak meaningless code on the keyboard and order to ensure their safety in the years of their code breaking success. But then a voila, he saw the meaningful text message preceding the Second World War. But host of changes at the German end in front of his eyes. apart from discovering a traitor in the form rendered their setup insufficient for the Thus, from the user’s point of view it of Hans-Thilo Schimdt who supplied the process of code breaking. It was at this was very friendly and therefore design of the Enigma machine, the French point that the Poles invited the British and commercially successful. Once the could achieve nothing in this regard. French cryptanalysis and sought their help. machine was made robust and its Poland, however, was desperate to They handed over their technologies and usefulness established the German military gather information regarding Germany’s made a fervent plea to carry on with the placed heavy orders for its purchase. In communications. It had gained process. Everyone could sense that a big 1925, Scherbius began mass production independence in the aftermath of the First war was approaching and the British of his machine for supply to the military World War but was afraid that Germany marshaled its strength to take up the forces. might any day lay claim to its territory. They Enigma challenge. SCIENCE REPORTER, APRIL 2012 32 Feature Article Every major user had tried to Alan Turing's office at Bletchley Park make his code more complex so that it became unbreakable. But in every age a solution had somehow sprung up. And therefore, no code had been absolutely secure. Cracking it at Bletchley On 4 September 1939, Alan Turing reported to Bletchley Park. It was actually a massive building in Buckinghamshire, about fifty miles northwest of London. Admiral Quex Sinclair had bought the house to serve as the base for the functioning of the General Code and Cipher School. It was undoubtedly a center of military activity but the group that arrived there, Turing decided that more developed machines especially in a mathematics paper in the included, had very little respect for formal had to be built to crack the Enigma codes. 1930s, was to break the rules of a fairly behavioural manners. Turing was the one who designed a rigid orthodoxy. No such machines existed There were mathematicians other new generation of bombes. Back in at the time, only calculating devices too than Turing. Two of them were fellow Princeton he had built an electronic crude to undertake any complex Cambridge mathematicians namely multiplier that could encipher messages mathematics, and certainly not Gordon Welchman and John Jeffreys. by multiplying large binary numbers programmable.” Leavitt is only correct There was another called Peter Twinn. Apart together. So he was the really experienced when he writes in such a manner. from mathematicians the team had one in this regard and the responsibility fell G.H. Hardy, the famous number experts from other areas of knowledge on his shoulders. theorist, had earlier summarily dismissed also. Hugh Alexander, the British chess In fact, Turing had been in love with the proposition of mathematicians making champion was there alongwith the writer machines all his life. In 1937, about a their discoveries by turning the handle of a Malcom Muggeridge. The military couple of years after he was elected a miraculous machine. Hardy simply establishment had also ensured the fellow at King’s College in Cambridge, represented the views of his peers. But services of winners in a competition to solve Turing saw his revolutionary paper come Turing was a different breed altogether and the Daily Telegraph crossword puzzle as fast out in the Proceedings of the London thus he could say at one place in his paper: as possible. Mathematical Society. It was titled “On “According to my definition, a number is The mathematicians staying at a low Computable Numbers, with an Application computable if its decimal can be written building called the Cottage first to the Entscheidungsproblem”. In it Turing down by a machine.” concentrated on the techniques of code proposed to build a machine that would Turing’s bombes kept the British breaking invented by the Poles. Rejewski determine the solvability of the classical armed forces informed about all the and his team had built machines to aid Entscheidungsproblem or the decision German measures.