In 1919 a Dutchman, Hugo Alexander Koch patented an invention which, in his own words, was a sort of secret writing machine. It was described in the patent "that steel wires on pulleys, levers, rays of light, or air, water, or oil flowing through tubes could transmit the enciphering impulse as well as electricity did" (Garlinski 9). Koch gave a great many other details about the machine, but he did not build this machine along those lines. Koch built the machine because he believed that it had some commercial value. So he set up a company under the name of the patent.

About three months later, an engineer named Arthur Scherbius was carrying out various experiments on this new machine and others like it. He determined that this machine was rather large and clumsy, sort of like a typewriter or a cash register. They were operated by electricity and worked on a rotor system. But even still, Scherbius was so very excited about the possibilities of this new rotor-ran encryption machine that he recommended it to the scientific director of the Institute of Criminology in Vienna, Dr. Siegfried Türkel. Türkel in turn wrote positively at length about the new machine.

During the next few years, the machine went through many fundamental changes as a result of the buying of Koch's patent. Koch's company started an extensive advertizing campaign in hopes of attracting large firms with hopes that they would buy it for commercial purposes. However, it did not meet with success; back in those years, industry was very unwilling to incur the considerable costs that came with purchasing something that would preserve their trade secrets. A brighter side appeared on the horizon in 1926, when the German navy, still small because of the Treaty of Versailles, began to take an interest in the machine. The high German naval ranks contacted the Berlin company and bought one machine. After careful study of the complicated mechanism it was decided that the machine would be brought into use the same year, and hence, a great number of them were ordered. And then in 1929, the German army, still small, but with great promise, followed the navy and decided that the machine would serve its purpose as well.

The machine continued to be offered on the open market. This was done most likely on purpose, for if advertising and sales had suddenly ceased, expert circles and foreign intelligence would surely have noticed. And the purchasing of the encryption machines by the Germans was made in the greatest secrecy.

Now it was certain that the machine would have a fine career, but it was still too early to know that history would associate it with one of the greatest secrets of the Second World War.

The machine was called the Enigma.

This paper on the Enigma has already described a little about the pre-war "history" of the machine. In addition, it will include a little on how the Enigma works, how it was broken, and it's importance in the war.

The Enigma machine was a very complicated piece of machinery.It had a keyboard with the twenty-six letters of the alphabet, which was connected electronically to three rotors with rings (this number became larger as the war went on, reaching even six by 1944) and from these led further connections to twenty-six electronically illuminated letters. The rotors each had a ring which held the twenty-six letters of the alphabet. By pressing a key, an electric current, supplied by a battery, passed through the machine and the rotors turned mechanically but not in unison. With the three rotors, every time one pushed a key, the first rotor would rotate one letter. This would happen twenty-six times until the first rotor had made a full rotation, and then the second one would start to rotate, etc. At the same time as one pressed the key, a light came on behind the ciphertext letter, which was always different from the original plaintext one. It worked in the reverse way as well. When someone else, using the Enigma with the same settings, depressed the ciphertext letter, the letter of the original message lit up. There was no need to incorporate '"encipher and decipher" modes into the Enigma machine, which made the operation of the machine a little less complex. This was the basic principle of the Enigma, reciprocity. So, in order to read messages enciphered on it, one needed a similar machine with an identical setting. The second principle of Enigma was that one letter put into the machine could never come out the exact same letter. This property was called exclusivity and it had a weakness. This was that by doing this, one is limiting himself to one specific type of encryption, and this was a blessing in disguise for the workers at Bletchley Park.

Even making the Enigma harder to crack was the fact that each of these rotors could be taken out and replaced in a different order. Plus, the rings on the rotors were put in a different order each day. For instance, on Tuesday, if the first rotor was set on "K", then perhaps on Wednesday, the ring would be set on "C", etc.

Furthermore there was the plugboard, which was built just like an old-time telephone switchboard. It was this switchboard that differed the military enigma from the commercial one. It had the affect of performing an extra switching of letters, both before entering the rotors, and after emerging from them. This was achieved by attaching wires, with plugs, into a plugboard with twenty-six holes. Until late 1938, the Germans usually only had six or seven pairs of letters connected with the plugboard. For the 26-letter Enigma with three rotors, there would be a 26 x 26 x 26 = 17576 possible conditions of the rotors. Until late 1938, there was a stock of just three rotors, which allowed a total of six arrangements. So, 6 x 17576 = 105456, different combinations in the alphabet. And when the Germans added rotor after rotor after rotor to the Enigma, that number escalated immensely.

Presumably the German authorities believed that these modifications to the commercial version of the Enigma made it practically unsolvable. They were sorely mistaken.

The cracking of the Enigma was possibly the most important thing that helped the Allies win World War II. And it wasn't the Americans who accomplished this outstanding feat. It wasn't even solely the British. The group that made the first strides toward the cracking of the Enigma were the Polish.

Marian Rejewski, Jerzy Rózycki, and Henryk Zygalski, three Polish mathematicians who had achieved status through their work on ciphers prior to the Enigma, were called upon to work on the Enigma. In the first half of 1938, the Polish hierarchy had found out about the Enigma through connections in the German company that was advertizing the machine. They knew that the Germans were using the Enigma in their naval and army forces, but rather than have the Germans compromise this information by telling their Allied friends, they decided to work on it themselves. So they bought themselves a few Enigmas, to have a chance to work on them first hand. And these three gentlemen, Rejewski, Rózycki, and Zygalski, were the main persons working on this all too important cipher machine.

Their first priority was to develop some kind of equipment which could in some way work out the Enigma settings, that is the position of the three rotors and the plugs. Rejewski designed a machine which would consist of six Enigmas connected together and called it the Bombe. The principle of it was that the rotors of these six machines revolved, powered by electricity, and in two hours tested every possible solution. Speed was of the essence and so it was devised that there would be six Bombes: one for each rotor position. When they reached the right solution, a light came on and the motor stopped automatically. This was the first primitive computer, without electronics or memory. The design, together with the plans, was sent to a firm and factory to be built as quickly as possible. By November 1938 the Bombes were ready and the process of reading German signals began. Alongside this solution, Zygalski's group devised another method, which was manual and not mechanical, called the perforated sheet. About one thousand holes were cut in a piece of paper according to a pre-determined pattern. Twenty-six of these sheets were required, one for each of the rotor positions. When they were laid on top of each other one by one, after some time, usually around the tenth sheet, in one place a hole appeared through all of them. This was the secret setting of the machine. Six complete sets of twenty-six sheets were needed, just like the six Bombes. The use of the sheets and the Bombes was a "practical and mechanical application of mathematical permutations" (Garlinski 37). Unfortunately the making of the sheets could not be entrusted to the firm and their resources, and the cryptoanalysists had to make them themselves. They not only had to calculate their layout, but they also had to cut out the holes to the last millimeter with a razor blade, which was an endless job. The first two sets of sheets were completed about the same time as the Bombes, towards the end of 1938. The sheets had the advantage over the Bombes that changes in the number of plugs in the plugboard did not affect their value, but it was still the notion of making the sheets.

Nevertheless, satisfaction at having both the Bombes and the perforated sheets was short lived. By late December 1938 a complication arose. The Germans once again made an alteration to the Enigma and the signal they were receiving became a long list of jumbled letters. The cipher equipment ingeniously and costly built by Zygalski's group, was now very slow in use. But the results already achieved, even if no German war plans were intercepted, were tremendous. They now knew that there were ways of cracking the machine's messages. It was just a matter of keeping up with the changes made by the Germans to the machine. If this could be accomplished, then it was very conceivable that the messages could be decrypted and read with great consistency.

Britain is a rather small country. But in spite of this, it has managed to build a immensely prosperous empire that spans the earth and govern it as well. This is all made possible because of the outstanding ability of the British to pick the right people for the right job. This is no less evident then in Bletchley Park, the institution where the real breaking of the Enigma took place.

First of all at Bletchley, there were the specialist cryptoanalysists, who had been working in the field since World War I. The most eminent of these was Alfred Dillwyn Knox.

During the First World War, "Dilly" Knox was plucked by the British from Cambridge and brought into naval intelligence in and around 1915. He was placed in the infamous "Room 40" and made a name for himself there when, while lying in a bath, he hit on the code used by the commander of the German navy to issue orders to his U boats.

At the end of the war, he was persuaded to stay in "Room 40" which later became the Government Code and Cipher School. It was there that the Enigma problem found him in the thirties. Like the analysists in Poland, he was able to use the German commercial model, but he had been unable to make the final breakthrough, although he had come very close.

In addition to Knox, other outstanding cryptoanalysists worked with him. There were mathematicians: C.H. Alexander, Charles Babbage, Peter Twinn, and George Welchman; writers and historians: Dr. Frank Adcock, Desmond McCarthy, and Angus Wilson; the eventual "inventor" of the computer, Alan Turing, and many, many more.

As the war began in England, much was moved out into the countryside to avoid bombing attacks. The Government Code and Cipher School was transferred to Bletchley Park, about 60 or so miles northwest of London. The numerous rooms were all panelled and electricity and plumbing were of the highest order. The whole estate was surrounded by barbed wire and patrolled by men of the British army. The Park immediately became too small, so they began to build huts and sheds and cafeterias in the park. About ten thousand people worked there, including cooks, janitors, and the cryptoanalysists.

The most important, the most closely guarded, and relatively the smallest focal point of the whole center was the small team of cryptoanalysists, whose task was to break the Enigma. Only about five-hundred or so people in Great Britain knew what they were doing. At the beginning, the team consisted of at the most ten people, with Knox and Twinn in charge, and assisted by two young and extremely talented women, Margaret Rock and Mavis Lever, plus Alan Turing, the brilliant mathematical mind. They all worked in a small whitewashed hut opposite the horse stable.

At first, the group met with little success, but all of that changed when the machine sent from Poland was delivered to the hut. Along with the Enigma model was sent details of how to produce Bombes and perforated sheets. Now they could begin really creative work which was aimed at developing aids for quickly discovering the German keys and breaking the secrets of the signals enciphered on the Enigma.

But the deciphering of the Enigma's signal was only the first hurdle to overcome at Bletchley. The deciphered message had to be translated into English and assessed by many different sets of people. Each section of the German armed forces used a different set of jargon in its signals, with abbreviations and such. This was very difficult to understand and very technical, demanding from the translator an excellent knowledge of the subject from a very many point of views. A number of new teams had to be created, to achieve these new projects now that the Enigma's messages were being read. They had to have good, fast communications, yet they could not meet the others working in the other departments they were associated with. Everyone was bound by the Official Secrets Act (Winterbotham 168), which they had signed to ensure more than top secret confidentiality in relation to the Enigma.

The information that was cracked in this way would have to be sent great distances to reach the right people quickly, and so it would be essential to use radio. But there were problems. The increase of radio traffic alone may alert the Germans that something was amiss. There also might be mistakes made by untrained operators which the German specialists would use to read those top-secret signals. If the enemy found out that the Enigma had been broken, the whole huge effort would be wasted and it would be back to the drawing board.

The need to transmit such information over great distances introduced the need for ciphers that could not be broken. The widely-known one-time pad system was used. The essence of the system is that the key, which is only known to the sender and the receiver, is used only once. It is not a popular technique, since it is not very suitable for widespread use. But, unless the key was captured, the cipher could not be broken. With time even more German signals were being read, but only the most important were sent on, and so this encryption method could be used. Only a very few people were used to run these signals through the airways. They were called the Special Liaison Unit (SLU).

This new organization needed a name to distinguish it easily from the other intelligence nets. F.W. Winterbotham, the leader of the organization, took suggestions from others on what to call it.

The name "Ultra Secret" was adopted; "Ultra" for short.

Enigma, which meant puzzle, was the machine which sent many to their grave a little bit early. Without the codes and the signals from the Enigma being deciphered, there would be, in my opinion, a very large German country, with a whole new map consisting of, not just West and East Germany, but also North and South. If it was not for the boys in Poland and the groups working at Bletchley, the Enigma possibly would have gone through the war without anybody having the slightest idea of what messages it was conveying. Considering all the pressure that these people had to go through, they should get a lot more credit than they now have. Before researching this project, I had never before heard of Alan Turing or even Dillwyn Knox. But considering how secret the Enigma was, I can understand the lack of knowledge among most people.

After all the codes were broken and most messages were being deciphered, the job was not done. Bletchley still had to accommodate for the changes the Germans made to the Enigma. Breaking one code was not enough, there was still very much to be done, considering the contacting of the people who needed to know what the codes said.

All the offices, barracks, and huts at Bletchley Park continued to work: the teleprinters carried typing, the experts continued to pore over their texts, deciphering signals at top speed, but the most important and the most dramatic period of the war had ended.

The war still continued in the Far East and the atom bomb had not yet been dropped, but the Enigma's decipherment and all its secrets, successes, achievements, and failures had played its part.

BIBLIOGRAPHY

Garlinski, Józef. The Enigma War. Charles Scriber's Sons, New York, NY.(c)1979.

Winterbotham, F.W. The Ultra Secret. Harper & Row, Publishers. SanFransisco, CA. (c)1974.

Bourdon, Georges. The German Enigma. J.M. Dent & Sons LTD. London, England. (c)1977.