Story of Alan Turing and the discovery of Enigma

The name of Alan Turing is one that is destined to remain etched in history. Although his, of history, was not revealed to the world until relatively late. The British scientist was a brilliant mathematician skilled in cryptography and logic, in our days recognized as one of the great pioneers of modern computing and as a great experimenter in applied mathematics.

His contribution during World War II was crucial, not only in deciphering the Nazi Enigma code, but also in actually shortening the duration of the fighting by a couple of years, saving some 14 million lives. In 2015, Turing's life, discoveries and subsequent drama, along with his controversial death, were the inspiration for The Imitation Game, a film directed by Morten Tyldum with an extraordinary Benedict Cumberbatch as the protagonist, which was able to tell the story of his genius and suffering.

Not everyone, however, knows who Alan Turing was, and how much of the technology we are accustomed to using in everyday life derives from his incredible work, which has remained hidden for too long.

Alan Turing: a story of genius and suffering

Alan Turing was born in London on June 23, 1912, from parents who were both engaged in India for the British royal government. Always a solitary soul, since childhood he was naturally interested in scientific subjects, especially logic and mathematics. Although he was certainly not at the top of his class, on the contrary, his report cards at school were very bad.

In middle school he was judged the worst student in the class, while in high school his mother received a letter from the principal, in which Alan was described as a problem child.

Science was his lifeline, a passion he shared with his classmate Christopher Morcom, by whom he was totally fascinated.

When his friend died of bovine tuberculosis in 1930, young Alan became even more closed in on himself and became obsessed with investigating all those areas of knowledge that could help him find an answer to Christopher's untimely end. So he ranged from biology, philosophy and metaphysics, but also mathematical logic and quantum mechanics, not forgetting the studies on morphogenesis.

The following year, we are then in 1931, thanks to his efforts he received a scholarship to King's College in London. Here he studied quantum mechanics and probability theory together with the Austrian logician Ludwig Wittgenstein, and after graduating in mathematics at Cambridge University he devoted himself mainly to cryptography, remaining in an academic environment, in particular in the universities of Cambridge, Princeton and Oxford.

Contrary to the widespread stereotype of the scruffy and fragile genius, Alan Turing was very attentive to his physical fitness, and very often ran at a competitive level. His routine led him to run more than 40 kilometers on foot, even distinguishing himself in the marathon with performances as a thirty-year-old almost equal to those of the Olympics.

Enigma and Cryptography

In 1939, when England entered the Second World War, Turing was hired to be part of the secret espionage service within a group of cryptanalysts at Bletchley Park, in the so-called Station X. The goal was to decrypt Nazi military messages encoded through the machine known as Enigma. During the conflict, the Germans in fact used to rely on Enigma to encrypt their war messages: being able to decrypt them meant having access well in advance to the future moves of the enemy army.

Alan Turing took part in the enterprise of deciphering this very complicated code in the then top secret cryptanalysis site, working hard in a team and proving to be a fundamental cog in the decryption of Enigma, considered a "simple, ingenious and extraordinarily complex" device, and present with a specimen at the Museum of Computing Instruments in Pisa.

Enigma was invented by the German engineer Arthur Scherbius after the First World War. It is a very unique machine that generated codes based on the exchange of signals. Its operation consisted in sending encrypted messages altered in form but not in content, to avoid that the encryptions could be deciphered in case the enemy would intercept them. Together with his friend, the Anglo-American mathematician Gordon Welchman, between the end of 1939 and the middle of 1940 Turing developed a machine called Bombe, a Polish word that indicates a type of ice cream, with which he was able to successfully decipher the transmissions of the Third Reich.

Not only that, he was able to develop a method known as Turingery that exploited the cryptographic errors of the opponents to decrypt the messages. If two messages were sent by mistake with the same encryption key, the Turingery allowed to extrapolate the code used to encrypt both communications and finally decrypt the content.

At the beginning of 1942 about 40 thousand messages were intercepted and decrypted, which doubled in a month, reaching the incredible total of two decrypted messages per minute. According to the British Prime Minister of the time, Winston Churchill, AlanTuring's work helped to reduce the war on the Old Continent from two to four years, saving about fourteen million lives.

Only in retrospect, and after the dissolution of military secrecy, the British government decided to spread the successes achieved by Turing and his team, both in decoding naval messages and in encrypting voice messages, with a system called Delilah, together with the very useful and providential invention of the bunburism procedure.

The contributions to science

In modern times, Turing's name is associated in particular with the machine and the tests that bear his name. The Turing machine is an entirely theoretical device consisting of an infinite, rewritable ribbon on which symbols can ideally be written, read and erased as you move back and forth along the same ribbon.

In fact, it is the ideal model of a machine designed to solve algorithms, developed by the English scholar at just 24 years old. Alan Turing himself described it as "an automatic machine" created to solve the decision problem, the Entscheidunsproblem, launched by mathematician and philosopher Gottfried Leibnitz in the 1700s. And, at present, the mathematical basis of digital computers.

The Turing test, however, was published for the first time in 1950 in the popular science magazine Mind, and is the greatest legacy left by the scholar in terms of artificial intelligence, of which he was undoubtedly a pioneer. According to this criterion it is possible to determine whether an artificial machine, or a computer, can be considered thinking. Over the years, the test has been reformulated several times and subject to harsh criticism.

After the end of the World War, Turing went to work at the National Physical Laboratory in London: here he devoted himself to the Automatic Computing Engine project, better known as ACE, that is the first digital electronic computer without military purposes. In the same years, he invested his genius in programming the first computers, and designed one of the first prototypes of virtual chess game. In parallel, his interest in biology, physiology, and neurology is well known.

The Fall and Death of Alan Turing

Although Alan Turing was elected a fellow of the Royal Society of London in March 1951 and was considered the creator of artificial intelligence and modern cognitive science, his downfall was sadly near. Indeed, in March 1952, he was charged with "gross indecency and sexual perversion" and sentenced to a year in prison just for being homosexual. And because of the alleged homosexual relationship with another man, 19-year-old Arnold Murray, later openly acknowledged.

During the trial, Turing declared that he felt no remorse or guilt for simply leading his life, and never organized a proper legal defense, considering his behaviors completely natural. To avoid jail time, however, he subjected himself to a chemical castration "therapy" to reduce libido, based on the synthetic estrogen known as diethylestilbestrol. To a friend, in that atrocious year, Turing wrote:

"The story of how all this came to be known is long and fascinating and I will tell it to you some day, but I have no time now. I will undoubtedly come out of this as a different man, but I don't know which one yet."

After three years of suffering, on June 7, 1954, Alan Turing's body was found lifeless next to a bitten apple covered in cyanide. The official verdict of death was suicide, but conspiracy theories were not long in coming. After hasty investigations that never found any clues that the scientist had really taken his own life, many people began to think that it would have been the British secret service to kill Turing, considered a threat for his knowledge of cryptanalysis and that, at least, according to some, he had ended up in the crosshairs of the Soviets to be recruited.

In 2009, then-British Prime Minister Gordon Brown publicly apologized on behalf of the British government for his treatment of Turing, and four years later, in 2013, he finally received a royal pardon from Queen Elizabeth II.