How the encryption codes of Nazi Germany were cracked. What is Enigma? enigma cipher machine who solved the turing code

Alan could have been born in India: his father, Julius, worked in the Indian Civil Service, and the family was living in India when Ethel Sarah became pregnant. But the couple decided that it would be better for the child to be born in London. Alan did just that.

From birth, Alan was, as they say, a strange child and at the same time a genius. According to some versions, he learned to read in just three weeks, and at the age of seven, Alan wanted to collect honey from wild bees during a picnic. To do this, he calculated the flight paths of insects among the heather and thus found the hive.

At the age of six, Alan Turing went to school, and at 13 he became a student at the well-known private school Sherborne. It is curious that in Sherborne the humanities were much more appreciated, and Alan's passion for mathematics was not encouraged. The headmaster wrote to the parents:

“I hope he doesn't try to sit on two chairs at once. If he intends to stay in a private school, then he should aim for an "education". If he is going to be exclusively a "scientific specialist", then a private school for him is a waste of time.

There, in Sherborne, Alan met the one who became his close friend and, perhaps, his first love, Christopher Markom. Unfortunately, the young man succumbed to a complication of bovine tuberculosis, leaving Alan in despair. It was this death that forced Turing to abandon his religious beliefs and made him an atheist.

“I am sure that I will not meet another companion so gifted and at the same time so charming,” Alan wrote to Markom’s mother. — I shared with him my interest in astronomy (which he introduced me to), and he did the same for me… I know that I must put into my work as much energy, if not as much interest, as I would have invested if he's alive, that's what he wants."

Correspondence with his friend's mother continued for many years after Morcom's death, and all letters were filled with tender memories of Christopher.

Alan entered King's College Cambridge, where his talents were already taken seriously. There he came up with the idea of ​​a universal machine - it was still an abstract idea, from which the concept of a computer was later born. Alan studied mathematics and cryptography.

Bletchley Park, Dilly Girls and Turing Bomb

Bletchley Park, also called "Station X" or simply "BP", was a large mansion in the center of England that was used during the Second World War for the needs of Britain's main cipher division. Asa Briggs, wartime historian and cipher clerk, said: “Bletchley needed exceptional talent, genius was needed. Turing was that genius."

Like any genius, he was strange. Colleagues called him by the short nickname Prof.

Historian Ronald Levina writes that Jack Good, a cryptanalyst who worked with Turing, had this to say about Alan:

“In the first week of June every year he would have a severe bout of hay fever and ride his bicycle to work wearing a gas mask to protect himself from pollen. His bike was broken: the chain flew off at regular intervals. Instead of fixing it, he counted the number of revolutions of the pedals through which the chain flew off, got off the bike and manually corrected it. On another occasion, he chained his mug to the radiator pipes so that it would not be stolen.”

Due to the fact that British men fought, most of Bletchley's workers were women. Cryptographers worked long hours decoding intercepted messages.

“In 1939, the work of a cryptographer, while demanding skill, was boring and monotonous,” says Andrew Hodges in Alan Turing’s Universe. “However, encryption was an essential attribute of radio communications. The latter was used in warfare in the air, at sea and on land, and the radio message for one became available to all, so the messages had to be made unrecognizable. They were not just made "secret", like spies or smugglers, the entire communication system was classified. And that meant errors, limitations, and hours of work on each post. However, there was no choice."

One of the most famous teams was a group of women called the Dilly Girls. They worked under the guidance of cryptanalyst Dilvin Knox. It was these women who deciphered the famous Enigma code, and Turing worked on the creation of a cryptanalytic machine. One of the "Dilli girls" was Joan Clarke.

Joan Clark

Turing became incredibly close to Joan, a rather introverted girl. She worked on deciphering the sea codes in real time - it was one of the most stressful jobs in Bletchley.

"We spent time together," she recalled in a 1992 interview with BBC Horizon. - We went to the cinema, but it was a big surprise for me when he said: “Will you agree to marry me?” I was surprised, but I didn’t doubt for a second, I answered yes, and he knelt in front of my chair and kissed me even though we didn't have physical contact. The next day we went for a walk after dinner. And then he said that he had homosexual inclinations. Naturally, this worried me a little - I knew for sure that it was forever.

Turing broke off the engagement a few months later, but despite this, they remained close friends.

Graham Moore, screenwriter of The Imitation Game, is sure that it was their strangeness that brought Alan and Joan together: "They were both outcasts, and this was their common, they looked at things differently."

gross obscenity

In December 1951, the 39-year-old Turing met Arnold Murray. He was 19. Unemployed handsome young man, thin, with big blue eyes, blond hair. Alan invited Arnold to a restaurant. After a while they saw each other again and spent the night together.

Although Alan tried to offer money to Arnold, Arnold said he didn't want to be treated like a prostitute. Several times he "borrowed" money from Turing, and after a while someone robbed Alan's house.

Arnold confessed to his lover that his friend did it. Alan reported the robbery to the police, but he had to confess his homosexuality.

Alan was sure that Parliament would soon legalize homosexual relations.

Arnold and Alan were put on trial. They were charged with "gross obscenity", both were found guilty. Arnold received a conditional release, and Alan was given a choice: a prison term or treatment of homosexuality with hormones.

Turing wrote to his friend Philip Hall: “I am sentenced to probation for a year and required to undergo medical treatment during the same period. Drugs are supposed to reduce sexual desire as long as it lasts ... Psychiatrists seem to have decided that it is useless to mess with psychotherapy.

And he also said: “No doubt, another person will come out of all this, but who exactly, I don’t know.”

poisoned apple

On June 8, 1954, Turing's housekeeper found him dead in his room. Next to him lay a bitten apple, which, most likely, became the cause of death. Alan was very fond of Disney's Snow White. According to biographers Hodges and David Leavitt, he took "particularly spicy pleasure in the scene where the Evil Queen plunges her apple into the poisonous drink".

Most likely, Alan poisoned the apple with cyanide and ate it.

In August 2009, British computer programmer John Graham-Cumming wrote a petition calling on the British government to apologize for the persecution of Turing for his homosexuality. It collected over 30,000 signatures and Prime Minister Gordon Brown released a statement of apology:

“Thousands of people demanded justice for Alan Turing, demanded to recognize that the attitude towards him was appalling. Turing was dealt with according to the law of that time, and we cannot turn back the clock, what was done to him was, of course, unfair. I and we all deeply regret what happened to him. On behalf of the British government and all those who live freely thanks to Alan's work, I say: "Forgive us, you deserve more."

Photo: Getty Images, REX

The history of the most famous electric rotary cipher machine - "Enigma" - begins in 1917 - with a patent received by the Dutchman Hugo Koch. The following year, the patent was bought by Arthur Scherbius, who began commercial activities by selling copies of the machine to both private individuals and the German army and navy.

The German military continues to improve Enigma. Without taking into account the adjustment of the position of the rings (German: Ringstellung), the number of different keys was 1016. In the late 1920s and early 1930s, despite the data on the car transmitted by the German aristocrat Hans Thilo-Schmidt, there were copies of commercial options, British and French intelligence did not began to take on the task of cryptanalysis. Probably by that time they already considered that the cipher was unbreakable. However, a group of three Polish mathematicians did not think so, and, until 1939, they carried out work on the "fight" against Enigma, and even knew how to read many messages encrypted by Enigma (in the version before the amendments to the encryption protocol of December 1938). Among the results transmitted to British intelligence before the capture of Poland by Germany were "live" copies of the Enigma, and the Bomba electromechanical machine, which consisted of six paired Enigmas and helped in decryption (the prototype for Alan Turing's later Bombe) , as well as unique cryptanalysis techniques.

1. What is the Enigma cipher machine?

The Enigma Cipher Machine was a portable cipher machine used to encrypt and decrypt secret messages. More precisely, Enigma is a whole family of electromechanical rotary machines that have been used since the 1920s.

Enigma was used for commercial purposes, as well as in military and government services in many countries of the world, but it was most widely used in Nazi Germany during World War II. It is the German military model that is most often the subject of discussion.

2. Work on hacking.

The burglary work was organized in Bletchley Park, today one of the UK's national pride. At the height of its activity, the Station X center numbered 12 thousand people, but despite this, the Germans did not learn about it until the very end of the war. The messages decoded by the center were classified as "Ultra" - higher than the previously used "Top Secret" (according to one version, the name of the entire British operation is "Operation Ultra"). The British took increased security measures so that Germany would not guess about the disclosure of the cipher. A striking episode is the case of the bombing of Coventry on February 14, 1940, about which British Prime Minister Winston Churchill knew in advance thanks to the decoding of the order. However, Churchill, relying on the opinion of analysts about the possibility of Germany to guess about Operation Ultra, decided not to take measures to protect the city and evacuate residents.

3. "Enigma", that is, "Riddle"!

During the Second World War, a stubborn struggle took place not only on the fronts of almost the whole world. No less stubbornly opposed to each other encryption services.

The Berlin engineer Arthur Scherbius named the first automatic cipher machine he invented in the history of cryptography with the Greek word "Enigma", that is, "Riddle". Despite such a loud name, it was quite simple to work on it: the text was typed on the keyboard and encrypted completely automatically. On the receiving side, it was enough to set your Enigma to a similar mode, and the codegram was also decrypted automatically.

But in order to solve the “mystery” when deciphering messages, the enemy had to know the system for replacing settings, and their alternation was unpredictable. A truly invaluable advantage of this machine was the ability to receive and transmit operational information in real time. This completely eliminated the losses associated with the use of signal tables, cipher pads, transcoding logs and other components of cryptography that require long hours of painstaking work and are associated with almost inevitable errors.

4. Efficiency and reliability of Enigma

The effectiveness and reliability of the Enigma was appreciated by the German General Staff: back in the late 20s and early 30s of the 20th century, it was adopted to equip all types of the German armed forces. However, around the same time, Polish intelligence managed to get hold of five such devices with impulse tuning kits. They handed over one typewriter to the British and French, but by the beginning of World War II, the Germans had completely rebuilt the tuning system, and the Allies were helpless in deciphering the intercepts.

Neither the French nor the Poles were able to benefit from the Enigma, but the copy that the British got was given to Sir Alistair Dennison, head of the State School of Codes and Cyphers (GSCS), which was located in the huge castle of Bletchley Park 50 miles from London. Several thousand employees worked in it, it was here that Operation Ultra was conceived and carried out, aimed at deciphering Enigma materials, supplied in abundance by the radio interception service.

Thanks to young and talented analysts - students of Cambridge and Oxford - the most modern technology was used during the operation. Computer Engineering. Its participants sacredly kept secret the methods of their work, not only during the war, but also for the next 30 years. The transcripts only went to the heads of the intelligence services of the armed forces and the head of the Intelligence Service, Sir Stuart Menzies. The rest of the authorities were sent only orders based on information obtained during Operation Ultra. But they were compiled in such a way that the Germans could not guess that they were obtained from the decoding of the Enigma materials.

Sometimes decoding played only a supporting role. These were cases where the Germans did not use radio communications, sending reports by wire, courier, dogs or pigeons. This happened often, because more than half of the information and orders were transmitted in similar ways during the Second World War.

Unfortunately, the English "boys from Bletchley" were not able to decipher all the codes. For example, the Triton cipher, introduced in the German Navy in 1942 and successfully operating for about a year, turned out to be a very tough nut to crack. Even when it was discovered in the GShKSH, it took so much time from interception to transmission of information to British sailors that the information lost all value.

It was even worse when commanders ignored Ultra's exact instructions unless they confirmed their own considerations. So, Field Marshal Montgomery, who was warned in time about the presence of two German tank formations in Arnhem, nevertheless ordered the regiments of the 1st Airborne Division to be thrown out in this area, where they were almost completely destroyed.

In Germany, sometimes they guessed about the disclosure of ciphers. So, in September 1942, the Germans discovered on a British destroyer a map of the routes of their convoys. And the Enigma's pulse tuning options were immediately replaced. In general, it would be foolish to consider the German staff officers profane in regard to cryptography. They knew well that any transpositional code is vulnerable. There were six cryptanalytic organizations in Germany. All of them were quite competent, but their main weakness was precisely decentralization, which always causes rivalry.

5. Cryptography in Moscow.

In Moscow, until 1938, the tasks of encoding and decryption were performed by the joint division of the NKVD and military intelligence. But when Beria became People's Commissar, he arrested and executed the head of the cryptographic service of the NKVD, Bokiy, and most of his employees. Since then, secret writing has been dealt with only in the GRU General Staff.

In February 1941, the cipher department of the NKVD was restored with the task of disclosing diplomatic correspondence. Naturally, the physical destruction of qualified specialists in the course of repressions could not but affect the effectiveness of the work of this department. However, the British still flattered themselves in vain on this score. Moscow received data on the GSHKSH back in 1939 from Kim Philby, who was then offered to penetrate there. This was done in 1942 by John Cairncross. He entered the service at Bletchley Park and supplied Moscow not only with the content of the Enigma decryptions, but also with genuine documents.

After Stalingrad, the British drastically reduced the amount of information provided from the Enigma, and the activities of Cairncross took on special significance for the Russians. True, on April 30, 1943, by personal order of Churchill, the Kremlin was nevertheless warned about the preparation of a major German operation near Kursk. But they already knew about this from their scouts, including from Cairncross. He informed about the location of the air bases of the Luftwaffe units aimed at operations in Operation Citadel, and two months before it began, Soviet aviation delivered three preemptive strikes against them. 17 airfields were destroyed, the Germans lost about 500 aircraft. But as London's control grew and transmission of information became almost impossible, Cairncross withdrew from Bletchley Park.

But why didn't they decipher the Enigma radio intercepts in Moscow? After all, they were well aware of its existence. Moreover, they had several quite serviceable such devices. Two were captured back in 1941. Three more - during the liquidation of the Stalingrad cauldron. Yes, and among the prisoners of war there were several cipher operators, whom the Chekists did not have to force to cooperate, which was done. However, only old radio intercepts were deciphered. The fact was that already in January 1943, the Germans introduced a number of additional levels of protection into their impulse tuning systems. Soviet cryptologists failed to "split" these novelties - the lack of the latest electronic technology affected.

6. Conclusion

During the entire period of active use of Enigma, various government organizations of European countries made attempts to “hack” the machine in order to protect against the growing threat from Germany. Enigma was necessary for Germany to carry out a quick and coordinated offensive against a number of countries in the framework of the Second World War. In the pre-war period greatest success in deciphering the Enigma messages, the Polish Cipher Bureau and personally Marian Rejewski reached. During World War II, the Enigma cryptanalysis was dominated by the British intelligence center Station X, also known as Bletchley Park.

"Enigma" (from the Greek. αἴνιγμα - a riddle) - a portable encryption machine. Initially, it was used for commercial purposes to preserve the secrecy of business correspondence; during the Second World War, the device was used by the German command.

Enigma cipher machine. Photo: www.globallookpress.com

How did Enigma encrypt the code?

The device consisted of a keyboard and a set of rotating disks - rotors. During the encryption process, the device changed one letter to another, for example, instead of the letter “A”, “T” was used, instead of “B”, “S”, etc. The code could be read by the one who knew the “key” to it. In essence, "Enigma" was a dynamic Caesar cipher.

When coding, the Germans used only 26 letters and sent messages in groups of five characters. Long messages were broken into parts, each of which used its own "key".

Who Invented Enigma?

This cipher machine was invented in 1915 by American Edward Hepburn. Subsequently, the device was used around the world and was significantly improved by the cryptographers of the Third Reich.

How difficult was decipher the code"Enigma"?

In the Third Reich, it was believed that Enigma could not be cracked, since it assumed 2 × 10 to the 145th degree of encoding options.

Who could decipher the Enigma code?

The Enigma code was deciphered in 1939 British mathematician Alan Turing, which allowed official London to know in advance about the plans of the Third Reich. In 2014, the film The Imitation Game was released in Russia, which is dedicated to this episode in history.

* Caesar's cipher is a type of substitution cipher in which each character is replaced by a character located at a certain constant number of positions to the left or to the right of it in the alphabet. For example, in a cipher with a right shift of 3, the letter A would be replaced by D, B would become D, and so on. The cipher is named after Roman Emperor Gaius Julius Caesar who used it for secret correspondence with his military leaders.

At almost any time of the year, the English countryside looks the same: green meadows, cows, medieval-looking houses and a wide sky - sometimes gray, sometimes dazzling blue. It was just transitioning from Mode 1 to the rarer Mode 2 as the commuter train sped me to Bletchley station. It is hard to imagine that the foundations of computer science and cryptography were laid in the midst of these picturesque hills. However, the upcoming walk through the most interesting museum dispelled all possible doubts.

Such a picturesque place, of course, was not chosen by the British by chance: an inconspicuous barracks with green roofs, located in a remote village, is just what was needed to hide a top-secret military facility, where they continuously worked on breaking the ciphers of the Axis countries. Bletchley Park may not be impressive from the outside, but the work that was done here helped turn the tide of the war.

Cryptohuts

In wartime, Bletchley Park was entered through the main gate, presenting a pass to the guards, and now they buy a ticket at the entrance. I lingered there a little longer to look at the adjoining gift shop and temporary exhibition dedicated to World War I intelligence technologies (which is also a very interesting topic, by the way). But the main thing lay ahead.

Actually, Bletchley Park is about twenty long one-story buildings, which are called hut in English, and are usually translated into Russian as “house”. I called them “huts” to myself, combining one with the other. In addition to them, there is a mansion (aka Mansion), where the command worked and distinguished guests were received, as well as several auxiliary buildings: former stables, a garage, residential buildings for staff.

Each house has its own number, and these numbers are of historical importance, you will definitely meet them in any story about Bletchley Park. In the sixth, for example, intercepted messages were received, in the eighth they were engaged in cryptanalysis (Alan Turing worked there), in the eleventh there were computers - “bombs”. The fourth house was later allocated for work on the Enigma version, which was used in the navy, the seventh - for the Japanese variation on the Enigma theme and other ciphers, in the fifth, transmissions intercepted in Italy, Spain and Portugal were analyzed, as well as German police encryption. Well, and so on.

You can visit the houses in any order. The decor in most of them is very similar: old furniture, old things, tattered notebooks, posters and maps from the Second World War. All this, of course, did not lie here for eighty years: the houses first passed from one state organization to another, then they were abandoned, and only in 2014 the restorers meticulously restored them, saving them from demolition and turning them into a museum.

This, as is customary in England, was approached not only carefully, but also with fiction: in many rooms, voices of actors and sounds are heard from hidden speakers that give the impression that work is in full swing around. You walk in and hear the sound of a typewriter, someone's footsteps and a radio in the distance, and then you "eavesdrop" on someone's lively conversation about a recently intercepted cipher.

But the real curiosity is projections. For example, this man, who, as it were, is sitting at the table, greeted me and briefly spoke about the local order.

The most interesting thing, of course, was to look at the desktop of Alan Turing. His office is located in the eighth house and looks very modest.

Well, you can look at Turing's creation itself - the machine for decoding the Enigma - in house number 11 - in the same place where the very first model of the "bomb" was assembled at one time.

Cryptological bomb

This may be news to you, but Alan Turing was not the first to decipher Enigma by brute force. His work is preceded by research by the Polish cryptographer Marian Rejewski. By the way, it was he who called the decryption machine a “bomb”.

Why "bomb"? There are several different versions. For example, according to one, the sort of ice cream beloved by Reevsky and colleagues was allegedly called that, which was sold in a cafe not far from the encryption bureau of the Polish General Staff, and they borrowed this name. A much simpler explanation is that in Polish the word "bomb" can be used for an exclamation like "eureka!". Well, a very simple option: the car was ticking like a bomb.

Shortly before the capture of Poland by Germany, Polish engineers handed over to the British all the developments related to the decoding of German ciphers, including the drawings of the "bomb", as well as a working copy of the "Enigma" - not a German, but a Polish clone, which they managed to develop before the invasion. The rest of the Poles' developments were destroyed so that Hitler's intelligence did not suspect anything.

The problem was that the Polish version of the "bomb" was designed only for the Enigma I machine with three fixed rotors. Even before the start of the war, the Germans commissioned improved versions of the Enigma, where the rotors were replaced every day. This made the Polish version completely unusable.

If you've watched The Imitation Game, you're already pretty familiar with Bletchley Park. However, the director could not resist and made several digressions from real historical events. In particular, Turing did not create a prototype of the "bomb" with his own hand and never called her "Christopher".

Popular English actor Cryptocode Podbirac as Alan Turing

Based on the Polish machine and the theoretical work of Alan Turing, the British Tabulating Machine Company engineers created the "bombs" that were supplied to Bletchley Park and other secret facilities. By the end of the war, there were already 210 cars, but with the end of hostilities, all the "bombs" were destroyed on the orders of Winston Churchill.

Why did the British authorities need to destroy such a beautiful data center? The fact is that the “bomb” is not a universal computer - it is designed exclusively for decoding messages encrypted by Enigma. Once this was no longer needed, the machines also became unnecessary, and their components could be sold.

Another reason may have been a premonition that the Soviet Union would not be Britain's best friend in the future. What if the USSR (or anywhere else) started using technology similar to Enigma? Then it is better not to demonstrate to anyone the ability to open its ciphers quickly and automatically.

Only two "bombs" survived from wartime - they were transferred to GCHQ, the UK Government Communications Center (consider the modern analogue of Bletchley Park). They say they were dismantled in the sixties. But GCHQ graciously agreed to provide the museum in Bletchley with old drawings of "bombs" - alas, not in best condition and not entirely. Nevertheless, enthusiasts managed to restore them, and then create several reconstructions. They are now in the museum.

Interestingly, during the war, the production of the first "bomb" took about twelve months, but the reenactors from the BCS Computer Conservation Society, starting in 1994, worked for about twelve years. Which, of course, is not surprising, given that they had no resources at their disposal other than their savings and garages.

How did Enigma work?

So, "bombs" were used to decrypt the messages that were obtained at the output after Enigma encryption. But how exactly does she do it? Of course, we will not analyze its electromechanical circuit in detail, but general principle work is interesting to know. At least it was interesting for me to listen and write down this story from the words of a museum worker.

The design of the "bomb" is largely due to the design of the "Enigma" itself. Actually, we can assume that the “bomb” is a few dozen “Enigmas” put together in such a way as to sort through the possible settings of the encryption machine.

The simplest "Enigma" is three-rotor. It was widely used in the Wehrmacht, and its design suggested that it could be used by an ordinary soldier, and not by a mathematician or engineer. It works very simply: if the operator presses, say, P, a light will turn on under one of the letters on the panel, for example, under the letter Q. It remains only to convert to Morse code and transmit.

An important point: if you press P again, there is very little chance of getting Q again. Because every time you press the button, the rotor moves one position and changes the configuration of the electrical circuit. Such a cipher is called polyalphabetic.

Look at the three rotors at the top. If you, for example, enter Q on the keyboard, then Q will first be replaced by Y, then by S, by N, then reflected (it will turn out K), changed again three times and the output will be U. Thus, Q will be encoded as U. But what if you type U? Get Q! So the cipher is symmetrical. This was very convenient for military applications: if two places had Enigmas with the same settings, messages could be freely transferred between them.

This scheme, however, has a big drawback: when you enter the letter Q, due to the reflection at the end, under no circumstances could you get Q. German engineers knew about this feature, but did not attach much importance to it, but the British found an opportunity to exploit it . How did the British know about the insides of the Enigma? The fact is that it was based on a completely non-secret development. The first patent for it was filed in 1919 and described a machine for banks and financial institutions that allowed the exchange of encrypted messages. It was sold on the open market, and British intelligence managed to acquire several copies. By their own example, by the way, the British Typex cipher machine was also made, in which the above-described flaw was corrected.

The standard Enigma had three rotors, but you could choose from five options in total and install each of them in any slot. This is exactly what is reflected in the second column - the numbers of the rotors in the order in which they are supposed to be put in the car. Thus, already at this stage, it was possible to get sixty options for settings. Next to each rotor is a ring with the letters of the alphabet (in some versions of the machine - the corresponding numbers). The settings for these rings are in the third column. The widest column is already an invention of German cryptographers, which was not in the original Enigma. Here are the settings that are set using the plug-in panel by pairing the letters. This confuses the whole scheme and turns it into a difficult puzzle. If you look at the bottom line of our table (the first day of the month), then the settings will be as follows: rotors III, I and IV are placed in the machine from left to right, the rings next to them are set to 18, 24 and 15, and then the letters N are connected on the panel with plugs and P, J and V and so on. When all these factors are taken into account, there are about 107,458,687,327,300,000,000,000 possible combinations - more than seconds have passed since the Big Bang. It is not surprising that the Germans considered this car extremely reliable.

There were many variants of the Enigma, in particular, a version with four rotors was used on submarines.

Enigma hack

Breaking the cipher, as usual, allowed the unreliability of people, their mistakes and predictability.

The Enigma manual says to choose three of the five rotors. Each of the three horizontal sections of the "bomb" can test one possible position, that is, one machine can run three out of sixty possible combinations at a time. To check everything, you need either twenty "bombs" or twenty consecutive checks.

However, the Germans made a pleasant surprise to the English cryptographers. They introduced a rule that the same position of the rotors should not be repeated within a month, and also for two days in a row. It sounds like it was supposed to increase reliability, but in reality it had the opposite effect. It turned out that by the end of the month, the number of combinations that needed to be checked was significantly reduced.

The second thing that helped with the decryption was traffic analysis. The British listened to and recorded the encrypted messages of Hitler's army from the very beginning of the war. There was no talk of decoding then, but sometimes the very fact of communication is important, plus such characteristics as the frequency at which the message was transmitted, its length, time of day, and so on. Also, using triangulation, it was possible to determine where the message was sent from.

A good example is the transmissions that came from the North Sea every day from the same locations, at the same time, on the same frequency. What could it be? It turned out that these were meteorological ships, which daily glorified weather data. What words can be contained in such a transmission? Of course, "weather forecast"! Such guesses pave the way for a method that today we call a plaintext attack, and in those days they called "clues" (cribs).

Since we know that "Enigma" never produces the same letters as the original message, we need to match the "hint" successively with each substring of the same length and see if there are any matches. If not, then it is a candidate string. For example, if we check the clue “weather in the Bay of Biscay” (Wettervorhersage Biskaya), then we first write it out against the encrypted string.

We see that the letter S is encrypted into itself. This means that the hint needs to be shifted by one character and checked again. In this case, several letters will match at once - move more. Matches R. Move twice more until we hit a potentially valid substring.

If we were dealing with a substitution cipher, then this could be the end of it. But since this is a polyalphabetic cipher, we need the settings and initial positions of the Enigma rotors. It was them who were picked up with the help of "bombs". To do this, a pair of letters must first be numbered.

And then, based on this table, draw up the so-called "menu" - a diagram that shows which letter of the original message (that is, "hints") into which letter is supposedly encrypted and in what position. According to this scheme, the “bomb” is configured.

Each of the reels can take one of 26 positions - one for each letter of the alphabet being sifted through. Behind each of the drums there are 26 contacts, which are connected with thick cables in such a way that the machine searches for the plug-in panel settings that give successive matches of the letters of the encrypted string with the hint.

Since the structure of the "bomb" does not take into account the switching device inside the "Enigma", it gives out several options in the course of work, which the operator must check. Some of them will not work simply because in Enigma only one plug can be connected to one socket. If the settings are not suitable, the operator starts the machine again to get the next option. In about fifteen minutes, the "bomb" will go through all the options for the selected position of the reels. If it is guessed correctly, then it remains to select the settings of the rings - already without automation (we will not dive into details). Then, on English Typex machines modified for compatibility with Enigma, the encryptions were translated into clear text.

Thus, operating with a whole fleet of "bombs", the British, by the end of the war, received actual settings every day before breakfast. In total, the Germans had about fifty channels, many of which broadcast much more interesting things than the weather forecast.

Allowed to touch

In the Bletchley Park Museum, you can not only look around, but also touch the decoding with your own hands. Including - with the help of touchscreen tables. Each of them gives his task. In this, for example, it is proposed to combine the sheets of Banbury (Banburismus). This is an early method of deciphering the Enigma, which was used before the creation of the "bombs". Alas, it was impossible to decipher something in this way during the day, and at midnight all the successes turned into a pumpkin due to another change in settings.

Fake "data center" in Hut 11

What is in house number 11, where there used to be a "server room", if all the "bombs" were destroyed in the last century? To be honest, I still hoped in the depths of my soul to come here and find everything in the same form as it once was. Alas, no, but the hall is still not empty.

Here are such iron structures with plywood sheets. Some show life-size photographs of the "bombs", others show quotes from the stories of those who worked here. They were mostly women, including from the WAF - the women's service of the RAF. The quote in the picture tells us that switching loops and looking after the "bombs" was not an easy task at all, but exhausting daily work. By the way, another series of projections is hidden between the dummies. The girl tells her friend that she had no idea where she would serve, and is completely amazed by what is happening in Bletchley. Well, I was also amazed by the unusual exhibit!

I spent a total of five hours at Bletchley Park. This was barely enough to take a good look at the central part and catch a glimpse of everything else. It was so interesting that I did not even notice how time passed until my legs began to ache and ask to go back - if not to the hotel, then at least to the train.

And besides the houses, dimly lit offices, restored "bombs" and long stands with accompanying texts, there was something to see. I already mentioned about the hall dedicated to espionage during the First World War, there was also a hall about the decryption of Lorenz and the creation of the Colossus computer. By the way, in the museum I also found the Colossus itself, or rather the part that the reenactors managed to build.

The most hardy already outside the territory of Bletchley Park is waiting for a small museum of computer history, where you can get acquainted with how computing technology developed after Turing. I also looked there, but I already walked at a fast pace. I have already seen enough of BBC Micro and Spectrum in other places - you can do it, for example, at the Chaos Constructions festival in St. Petersburg. But you won’t find a live “bomb” anywhere.

Based on the materials of the dissertation "Ciphering machines and devices for decryption during the Second World War", defended at the University of Chemnitz (Germany) in 2004.

Introduction. For the general public, the word "Enigma" (in Greek - riddle) is synonymous with the concepts of "cipher machine" and "code breaking", which is taken care of by films about submarines and similar novels that have little to do with reality. Little is known about the fact that there were other cipher machines, for which special decryption machines were created to "break", and about the consequences that this had in the Second World War, little is known about this to the general public.

But we will not deal with this issue, but will limit ourselves to the scientific, technical and organizational circumstances that contributed to the disclosure of German encryption codes. And what is especially important, how and why it was possible to develop machine methods of “hacking” and successfully use them.
Breaking the Enigma codes and the codes of other cipher machines provided the Allies with access not only to military-tactical information, but also to information from the Foreign Ministry, police, SS and railway. This also includes messages from the Axis countries, especially Japanese diplomacy, and the Italian army. The Allies also received information about the internal situation in Germany and its allies.

Thousands of Secret Service teams worked on deciphering the codes in England alone. This work was personally supervised by the Prime Minister of England, Winston Churchill, who knew about the importance of this work from the experience of the First World War, when he was the Minister of the Navy of the British government. Already in November 1914, he ordered to decipher all intercepted enemy telegrams. He also ordered the previously intercepted telegrams to be deciphered in order to understand the mindset of the German command. This is a testament to his foresight. The most famous result of this activity of his is forcing the entry of the United States into the First World War.
Equally far-sighted was the creation of English listening stations - then it was a completely new idea - especially listening to the radio traffic of enemy ships.

Even then and between the two world wars, Churchill equated such activities with a new type of weapon. Finally, it was clear that it was necessary to classify their own radio communications. And all this had to be kept secret from the enemy. There are great doubts that the leaders of the Third Reich were aware of all this. In the leadership of the Wehrmacht (OKW) there was a department with a small number of cryptologists and with the task of "developing methods for disclosing enemy radio messages", and it was about front-line radio reconnaissance officers who were charged with providing front-line commanders with tactical information on their sector of the front. In the German army, the encryption machines used were evaluated not by cryptologists (in terms of encryption quality and hacking capabilities), but by technical specialists.

The Allies followed the gradual improvement of German encryption technology and also improved the methods of breaking encryption codes. The facts that testified to the awareness of the allies, the Germans attributed to betrayal and espionage. In addition, in the Third Reich there was often no clear subordination, and the encryption services of different branches of the military not only did not interact with each other, but also hid their skills from cryptographers of other branches of the military, since “competition” was in the order of things. The Germans did not try to unravel the encryption codes of the allies, since they had few cryptologists for this, and those that were, worked in isolation from each other. The experience of British cryptologists showed that the joint work of a large team of cryptologists made it possible to solve almost all the tasks. Towards the end of the war, a gradual transition began in the field of encryption from machine-based work to computer-based work.

Cipher machines in military affairs were first used in Germany in 1926. This prompted potential adversaries of Germany to join in the development of their own methods of encryption and decryption. For example, Poland took up this issue, and at first she had to develop the theoretical foundations of machine cryptology, since "manual" methods were not suitable for this. A future war would require thousands of radio messages to be deciphered daily. It was Polish specialists who in 1930 were the first to start work on machine cryptological analysis. After the outbreak of war and the occupation of Poland and France, these works were continued by British specialists. The theoretical work of the mathematician A. Turing was especially important here. Beginning in 1942, the disclosure of encryption codes became extremely important, as the German command increasingly used radio communications to transmit their orders. It was necessary to develop completely new ways of cryptological analysis for decryption machines.

History reference.
Julius Caesar was the first to use text encryption. In the 9th century, the Arab scholar Al-Kindi first considered the problem of deciphering a text. The works of Italian mathematicians of the 15th-16th centuries were devoted to the development of encryption methods. The first mechanical device was invented in 1786 by a Swedish diplomat, and such a device was at the disposal of the American President Jefferson in 1795. It was only in 1922 that this device was improved by the US Army cryptologist Mowborn. It was used to encrypt tactical messages until the outbreak of World War II. Patents to improve usability (but not encryption security) have been issued by the US Patent Office since 1915. All this was supposed to be used to encrypt business correspondence. Despite numerous improvements in devices, it was clear that only short texts were encrypted.

At the end of the First World War and in the first years after it, there are several inventions created by amateurs for whom it was a kind of hobby. Let's name two of them: Hebern (Hebern) and Vernam (Vernam), both Americans, neither of them, most likely, heard about the science of cryptology at all. The last of the two even implemented some operations of Boolean logic, which at that time very few people knew about, except for professional mathematicians. Professional cryptologists took up further improvement of these encryption machines, which made it possible to increase their security against hacking.

Since 1919 German designers also begin to patent their developments, one of the first was the future inventor of Enigma Arthur Scherbius (1878 - 1929). Four variants of similarly designed machines were developed, but there was no commercial interest in them, probably because the machines were expensive and difficult to maintain. Neither the Navy nor the Foreign Ministry accepted the proposals of the inventor, so he tried to offer his encryption machine to the civilian sectors of the economy. The army and the Foreign Ministry continued to use book encryption.

Arthur Scherbius went to work for a firm that bought his patent for a cipher machine. This firm continued to improve Enigma even after the death of its author. In the second version (Enigma B), the machine was a modified electric typewriter, on one side it had an encryption device in the form of 4 interchangeable rotors. The firm advertised the machine widely and advertised it as unbreakable. The officers of the Reichswehr became interested in her. The fact is that in 1923 Churchill's memoirs were published, in which he spoke about his cryptological successes. This caused shock among the leadership of the German army. German officers found out that most of their military and diplomatic communications had been deciphered by British and French experts! And that this success was largely determined by the weakness of the amateurish encryption invented by amateur cryptographers, since military German cryptology simply did not exist. Naturally, they began to look for reliable ways to encrypt military messages. Therefore, they developed an interest in Enigma.

Enigma had several modifications: A, B, C, etc. Modification C could perform both encryption and decryption of messages; she did not require complex maintenance. But its products were not yet resistant to hacking, because the creators were not advised by professional cryptologists. It was used by the German Navy from 1926 to 1934. The next modification of Enigma D was also a commercial success. Subsequently, since 1940, it was used in railway transport in the occupied regions of Eastern Europe.
In 1934 in the German navy began to use the next modification of the Enigma I.

It is curious that Polish cryptologists tried to decipher German radio messages classified by this machine, and the results of this work became somehow known to German intelligence. At first, the Poles were successful, but the German intelligence “watching” them informed their cryptologists about this, and they changed the ciphers. When it turned out that Polish cryptologists could not crack Enigma-1 encrypted messages, this machine was also used by the ground forces - the Wehrmacht. After some improvement, it was this cipher machine that became the main one in the Second World War. Since 1942, the German submarine fleet has adopted the Enigma-4 modification.

Gradually, by July 1944, control over the encryption business was transferred from the hands of the Wehrmacht to the roof of the SS, the main role here was played by the competition between these branches of the armed forces. From the very first days of WWII, the armies of the USA, Sweden, Finland, Norway, Italy and other countries are saturated with encryption machines. In Germany, machine designs are constantly being improved. The main difficulty in this was caused by the inability to find out whether the enemy is able to decipher the texts encrypted by this machine. Enigma of various modifications was introduced at levels above the division, it continued to be produced after the war (model "Schlüsselkasten 43") in Chemnitz: in October 1945. 1,000 pieces were produced, in January 1946. - Already 10,000 pieces!

Telegraph, historical background.
The advent of electric current caused the rapid development of telegraphy, which, not by chance, took place in the 19th century in parallel with industrialization. driving force were railways who used the telegraph for the needs of railway traffic, for which various devices such as pointers were developed. In 1836, the Steinhel device appeared, and in 1840 it was developed by Samuel Morse (Samuel MORSE). Further improvements came down to the Siemens and Halske printing telegraph (Siemens & Halske, 1850), which converted received electrical impulses into readable type. And invented in 1855. Hughes, the printing wheel, after a series of improvements, served well into the 20th century.

The next important invention to speed up the transfer of information was created in 1867 by Wheatstone: punched tape with Morse code, which the device felt mechanically. The further development of telegraphy was hampered by the insufficient use of bandwidth wires. The first attempt was made by Meyer (B.Meyer) in 1871, but it failed because it was prevented by different length and number of impulses in Morse letters. But in 1874, the French engineer Emile Baudot managed to solve this problem. This solution became the standard for the next 100 years. The Bodo method had two important features. First, it became the first step towards the use of binary calculus. And secondly, it was the first reliable multi-channel data transmission system.

The further development of telegraphy rested on the need to deliver telegrams with the help of postmen. A different organizational system was required, which would include: a device in every house, servicing it by special personnel, receiving telegrams without the help of personnel, constant inclusion in the line, issuing texts page by page. Such a device would only have prospects of success in the United States. In Europe, until 1929, the postal monopoly prevented the appearance of any private device for transmitting messages, they had to be only at the post office.

The first step in this direction was taken in 1901 by the Australian Donald Murray. He, in particular, modified the Baudot code. This modification was the standard until 1931. He did not have commercial success, since he did not dare to patent his invention in the United States. Two American inventors competed in the USA: Howard Krum and E.E. Kleinschmidt. Subsequently, they merged into one firm in Chicago, which began to produce equipment in 1024, which enjoyed commercial success. Several of their machines were imported by the German firm Lorenz, installed in post offices and obtained a license to produce them in Germany. Since 1929, the postal monopoly in Germany has been abolished, and private individuals have access to telegraph channels. The introduction in 1931 of international standards for telegraph channels made it possible to organize telegraph communication with the whole world. The same devices began to be produced since 1927 by Siemens and Halske.

For the first time, the 27-year-old American Gilbert Vernam, an employee of ATT, managed to combine the telegraph with a cipher machine. In 1918 he applied for a patent in which he empirically used Boolean algebra (of which, by the way, he had no idea and which was then being studied by several mathematicians around the world).
A great contribution to cryptology was made by the American officer William Friedman, who made American cipher machines practically unbreakable.

When Siemens and Halske telegraph machines appeared in Germany, the German navy became interested in them. But his leadership was still under the impression that the British during the First World War had cracked the German codes and read their messages. Therefore, they demanded that the telegraph apparatus be connected to the cipher machine. This was then a completely new idea, because encryption in Germany was done manually and only then the ciphertexts were transmitted.

In the USA, this requirement was met by Vernam devices. In Germany, this work was undertaken by Siemens and Halske. They filed their first open patent on this topic in July 1930. By 1932 a workable apparatus was created, which at first was freely sold, but since 1934. was classified. Since 1936 these devices began to be used in aviation, and since 1941. - and ground forces. Since 1942 began machine encryption of radio messages.

The Germans continued to improve various models of encryption machines, but in the first place they put the improvement of the mechanical part, referring to cryptology in an amateurish way, manufacturing firms did not involve professional cryptologists for consultations. Great importance for all these problems, the work of the American mathematician Claude Shannon, who has been well-read since 1942, had. worked at Bell Labs and conducted secret mathematical research there. Even before the war, he was famous for proving the analogy between Boolean algebra and relay connections in telephony. It was he who discovered the "bit" as a unit of information. After the war, in 1948 Shannon wrote his main work "The Mathematical Theory of Communications". After that, he became a professor of mathematics at the university.

Shannon was the first to consider the mathematical model of cryptology and developed the analysis of ciphertexts by information-theoretical methods. The fundamental question of his theory is: "How much information does the encrypted text contain compared to the clear text?" In 1949 he published The Theory of Communications. secret systems in which he answered this question. The analysis carried out there was the first and only one to quantify the reliability of the encryption method. Analysis after the war showed that neither German nor Japanese cipher machines were unbreakable. In addition, there are other sources of information (for example, intelligence) that greatly simplify the task of deciphering.

The position of England forced her to exchange long ciphertexts with the United States, it was the great length that made their decipherment possible. In a special department of the British secret service M 16, a method was developed that increased the degree of secrecy of the message - ROCKEX. The American method of encryption for the Ministry of Foreign Affairs was hacked by German specialists and the corresponding messages were decrypted. Upon learning of this, the United States in 1944. replaced an imperfect system with a more reliable one. Around the same time, the German Wehrmacht, the Navy and the Foreign Ministry also changed the encryption technology to a newly developed one. Soviet encryption methods were also insufficiently reliable, which is why they were hacked by American services and many Soviet intelligence officers who were spying on the American atomic bomb were identified (Operation Venona - breaking).

Breaking.
Now let's talk about HACKING German cipher machines by the British, that is, machine guessing the way texts are encrypted in them. . This work received the English name ULTRA. Non-machine decryption methods were too laborious and unacceptable in war conditions. How were the English deciphering machines arranged, without which the Allies could not have gained an advantage over the German cryptographers? What information and textual material did they need? And was there a mistake by the Germans here, and if so, why did it happen?

First, the scientific and technical foundations.
First, a preliminary scientific work, since it was necessary, first of all, to analyze the algorithms cryptologically and mathematically. This was possible because ciphers were widely used by the German Wehrmacht. Such an analysis required not only ciphertexts obtained by eavesdropping, but also plaintexts obtained by espionage or theft. In addition, different texts were needed, encrypted in the same way. At the same time, a linguistic analysis of the language of the military and diplomats was carried out. With long texts, it became possible to mathematically establish the algorithm even for an unfamiliar cipher machine. Then it was possible to reconstruct the car.

For this work, the British brought together approximately 10,000 people, including mathematicians, engineers, linguists, translators, military experts, and other employees to sort data, verify and archive it, and maintain machines. This association was called BP (Bletchley Park - Bletchley Park), it was personally controlled by Churchill. The information obtained turned out to be a powerful weapon in the hands of the allies.

How did the British take possession of the Wehrmacht Enigma? Poland was the first to decipher the German codes. After the First World War, it was in constant military danger from both of its neighbors - Germany and the USSR, who dreamed of regaining the lands lost and transferred to Poland. In order not to face surprises, the Poles recorded radio messages and deciphered them. They were greatly alarmed by the fact that after the introduction in February 1926. in the German Navy Enigma C, as well as after its introduction in the ground forces in July 1928. they could not decipher messages encrypted by this machine.

Then the BS4 department of the Polish General Staff suggested that the Germans had machine encryption, especially since the early commercial versions of Enigma were known to them. Polish intelligence confirmed that in the Wehrmacht from June 1, 1930. Enigma 1 is used. Poland's military experts failed to decipher the German messages. Even having obtained documents for Enigma through their agents, they could not succeed. They concluded that there was a lack of scientific knowledge. Then they instructed three mathematicians, one of whom studied in Göttingen, to create a system of analysis. All three received additional training at the University of Poznań and were fluent in German. They managed to reproduce the Enigma device and create a copy of it in Warsaw. We note the outstanding achievements in this of one of them, the Polish mathematician M. Reevsky (1905 - 1980). Although the Wehrmacht was constantly improving the encryption of its messages, Polish specialists were able to do so until January 1, 1939. decrypt them. After that, the Poles began to cooperate with the allies, to whom they had not reported anything before. Such cooperation, in view of the obvious military danger, was already expedient. July 25, 1939 they gave the British and French representatives all the information they knew. On August 16 of the same year, the Polish "gift" reached England, and English experts from the newly created VR decryption center began to work with it.

British cryptologists after the First World War were reduced, they remained only under the roof of the Foreign Office. During the war in Spain, the Germans used Enigma D, and the British cryptologists who remained in the service under the guidance of the eminent philologist Alfred Dillwyn (1885-1943) continued to work on deciphering German messages. But purely mathematical methods were not enough. By this time, at the end of 1938. Alan Turing, a mathematician from Cambridge, was among the attendees of the English courses for the training of cryptographers. He took part in the attacks on Enigma 1. He created an analysis model known as the "Turing machine", which made it possible to assert that the decryption algorithm necessarily exists, it only remained to open it!

Turing was included in the BP as a conscript. By May 1, 1940. he made serious progress: he took advantage of the fact that every day at 6 o'clock in the morning the German weather service transmitted an encrypted weather forecast. It is clear that it necessarily contained the word "weather" (Wetter), and that the strict rules of German grammar predetermined its exact position in the sentence. This allowed him to eventually come to a solution to the problem of breaking the Enigma, and he created an electromechanical device for this. The idea came to him at the beginning of 1940, and in May of the same year, with the help of a group of engineers, such a device was created. The task of deciphering was facilitated by the fact that the language of German radio messages was simple, expressions and individual words were often repeated. German officers did not know the basics of cryptology, considering it insignificant.

The British military, and especially Churchill personally, demanded constant attention to the decoding of messages. Since the summer of 1940 the British deciphered all messages encrypted with Enigma. Nevertheless, British specialists were constantly improving the deciphering technique. By the end of the war, British decoders had 211 deciphering devices operating around the clock. They were served by 265 mechanics, and 1675 women were involved in the duty. The work of the creators of these machines was appreciated many years later when they tried to recreate one of them: due to the lack of necessary personnel at that time, the work to recreate famous car lasted for several years and remained unfinished!

The instruction for the creation of decrypting devices, created then by Dühring, was banned until 1996 ... Among the means of decryption was the method of "forced" information: for example, British planes destroyed the pier in the port of Calle, knowing that a message from the German services would follow about this with a set known to the British in advance words! In addition, the German services transmitted this message many times, each time encoding it in different ciphers, but word for word ...

Finally, the most important front for England was the submarine war, where the Germans used a new modification of the Enigma M3. The English fleet was able to remove such a machine from a German submarine they had captured. On February 1, 1942, the German Navy switched to using the M4 model. But some German messages, encrypted in the old way, mistakenly contained information about the design features of this new car. This greatly facilitated the task of Turing's team. Already in December 1942. Enigma M4 was hacked. December 13, 1942 the British Admiralty received accurate data on the location of 12 German submarines in the Atlantic ...

According to Turing, in order to speed up decryption, it was necessary to switch to the use of electronics, since electromechanical relay devices did not perform this procedure quickly enough. On November 7, 1942, Turing went to the United States, where, together with a team from Bell Laboratories, he created an apparatus for top-secret negotiations between Churchill and Roosevelt. At the same time, under his leadership, American deciphering machines were improved, so that the Enigma M4 was broken completely and provided the British and Americans with comprehensive intelligence information until the end of the war. Only in November 1944 did the German command have doubts about the reliability of their encryption technology, but this did not lead to any measures ...

(Translator's note: Since, starting from 1943, the Soviet intelligence officer Kim Philby was at the head of the British counterintelligence, all the information was immediately sent to the USSR! Some of this information was sent Soviet Union and officially through the British office in Moscow, and also semi-officially through Alexander Rado, the Soviet resident in Switzerland.)

Chiffriermaschinen und Entzifferungsgeräte
im Zweiten Weltkrieg:
Technikgeschichte und informatikhistorische Aspekte
Von der Philosophischen Fakultät der Technischen Universität Chemnitz genehmigte
Dissertation
zur Erlangung des academischen Grades doctor philosophiae (Dr. phil.)
von Dipl.-Ing.Michael Pröse