March 7, 2011

The Enigma Machine Part I Polish Code Breakers

Poles Crack the Enigma (00:03:36m)

Original Logo of Enigma
The fundamental design of what was to become the famous Enigma Machine was in fact developed by four different inventors over a three year period. They all shared one thing in common, the vision of building a cipher machine using rotors to encrypt letters of the alphabet.

The first inventor was an American by the name of Edward H. Hebern (1917) who made the first patent claim, followed by Arthur Scherbius (Germany -1918), Hugo Koch (Netherlands-1919) and Arvid Gerhard Damm (Sweden -1919). Among the four only Scherbius found financial success with his machine.

Enigma Machine

Koch sought to promote his version of the Enigma for civilian, and commercial applications by which large companies could preserve their trade secrets in code.  Conversely,  Arthur Scherbius, a Berlin engineer envisaged military applications for his design and started a company to manufacture and sell  what he called the Enigma. By 1926 every German army division, ship, and submarine had an Enigma, and through the next twenty years its design was improved many times over and its function made much more complex. By the end of World War II, there was estimated to have been up to 120,000 Enigma machines in use by the German Wermacht.
As early as mid 1928, the Poles had been able to purchase a commercial model of the Enigma and began studying its' components.Soon after they began to make their first attempts at breaking the German ciphers. Messages were being intercepted by four Polish ELINT stations, in Warsaw, Starogard near Gdansk (or then Danzig), in Poznan and in Krzeslawice near Cracow.

University of Poznan
When their early attempts proved unsuccessful, the Poles realized that the ciphers would be difficult to break. The Ciphers Office (Biuro Szyfrów) of the Polish Army's General Staff sought the help of mathematicians, and in January 1929 they approached the Dean of the Department of Mathematics, Professor Zdzislaw Krygowski at the University of Poznan. The Dean submitted a list recommending some of his highest graduating students and twenty of them began working at the Ciphers Office,later graduating from a cryptography course that was also offered by that Office.

The students were sworn to secrecy concerning the plans of the course and their involvement in it. Overseeing all activities were two officers from the Polish General Staff in Warsaw, Major Franciszek Pokorny and Lt. Maksymilian Ciezki.

The best graduates were: Marian Rejewski, Jerzy Rozycki and Henryk Zygalski who worked at the University as well as secretly working for the General Staff's Ciphers Office. Rejewski himself spent about twelve hours each week huddled in a secret underground vault that was referred to as the "Black Chamber".

Marian Rejewski
In 1930, the German military introduced innovations to its design - a commutator or plugboard which consisted of 26 connections as well as the addition of three spinning rotors. It gave the Enigma an enormous range of cipher combinations, a total number that could only be expressed by 34 digits followed by 51 zeros. The Germans believed that it was virtually impossible for an enemy to even chance upon the right setting. Their arrogance, and ultimate carelessness proved them wrong. Despite efforts by many of the Allies, Polish cryptologists were the first to achieve success. They made significant and rapid progress during the years preceding World War II, and had already been deciphering and reading secret German transmissions.

Jerzy Rozycki
Of the original team of Polish mathematicians, by 1930, only eight students remained, working under the direction of Rejewski. Through an elaborate series of mathematical calculations Rejewski was able to arrive at a partial and quick solution to the Enigma Code, however, it only applied to the commercial model. A new branch of the Cipher's Office opened in Poznan, an operation shrouded in the utmost secrecy and one in which Rejewski, and his colleagues were immediately assigned to work. Two years later the team was relocated to Warsaw to begin work on the Enigma, where they successfully decoded a German Navy four letter cipher.

Rejewski, the leading cryptologist of the group, was searching for a new way of breaking the German code and developed a system of decryption based on mathematical equations. Polish Intelligence had in it's possession a genuine Enigma machine, albeit the commercial model, but nevertheless still an invaluable resource. The military Enigma was much more complicated and produced an infinite number of computations and permutations.

Henryk Zygalski
The Enigma was an extremely complicated electro-mechanical system based on drums or rotors for encoding. The machine very much resembles a typewriter with the addition of a panel built into its lid in which were inserted 26 small glass windows indicating each letter of the alphabet and on the underside of the panel was an equal number of tiny lamps. Inside the machine, mounted on one axle were 3 rotating drums and a reflector connected by an elaborate system of wiring which was powered by either electricity or battery. At the stroke of a key, two things occurred: one or more of the rotors would revolve, and the glow lamps would simultaneously light up next to the letter above it. So by typing a plain text in ordinary language, the keys made the appropriate windows illuminate.

But for the purpose of conducting a secret communication, sender and receiver had to possess a cipher, or "key ", a device which encrypted each letter through the manipulation of numerous levers and knobs.

Another breakthrough came in 1931 when Polish Intelligence joined forces with its counterpart, the French Deuxieme Bureau. Their collaboration eventually led to contact with an important agent operating within the Reichswehr Cipher's Office. As a result, Rejewski obtained a description of the militarized version of the Enigma, as well as old key tables. With these new leads, he was able to eliminate many previously unknown variables in the "permutation-like" equation he had originally created. By December 1932 Rejewski reconstructed the Enigma's internal connections.

The Cipher Bureau at Poznan was disbanded by the summer of 1932 and by the following September Rejewski in the capacity of a civilian employee, joined the Cipher Bureau at the General Staff building of Saxon Palace in Warsaw, along with Zygalski and Różycki.

Saxon Palace, Warsaw
In January 1933, two other cryptologists collaborated with Rejewski's work and in the same month decrypted the first German messages. From then on, the General Staff were able to discover secret information transmitted by the German Amy, Navy, Air Force, as well as the Ministry of Foreign Affairs.

The Polish Army's General Staff placed an order the very next month at the AVA Radio Workshops in Warsaw to build copies of the military Enigma. At the time however, the General Staff had in its possession only one Enigma which was a commercial model and lacked the front panel auxiliary connectors that made the code stronger.By the middle of 1934, about fifteen "made in Poland" Enigma's had been produced and delivered and by the of August 1939 production had increased to seventy such units. All were produced at the AVA Radio Manufacturing Company located at 34 Nowy Swiat Street in Warsaw under the auspices of its engineer, the brilliant Antoni Palluth.

In his mathematical analysis, Rejewski was able to obtain positive results using group theory. The first break came from the French secret service which possessed some documents on machine ciphers. It didn't contribute to cracking the Enigma code but helped in the process of achieving it. The documents (dated in 1932) provided real coded messages sent at specific times in that year. When the Poles compared the old messages that they had intercepted, to the key settings, and combined it to mathematical analysis - they hit the jackpot.

Kabaty Forest in Winter
The Poles easily figured out its inner wiring. It was not difficult for them to discover that the wiring of the ring was actually in the same alphabetical order as they appeared on the German typewriter, so precise were the Germans for ordung (order)!

The General Staff's Cipher Office, in 1934, established a new site for their German branch (BS-4) in the Kabaty Forest located near Warsaw. It was there that Rejewski and his colleagues worked until the outbreak of World War II. Although the French assisted the Polish team with the Enigma code break, all material was exclusively in the hands of the Poles until July 1939.

Just two weeks before the conference in Munich on September 14, 1938 the Germans had made drastic changes to their methods of Enigma encryption. They developed a new key which seemed to be more complicated, but did not deter the work of the Polish cryptologists. They set about to resolve the problem and invented the first mechanical pseudo-computers to facilitate their decoding. In October 1938, Rejewski designed the machines "bomba kryptologiczna" (cryptologic bomb) as well as a "cyclometer" machine which was immediately put into production at the AVA workshops. The "cyclometer" machine was essential in helping to assess the pattern of the secret key.

At the same time, the Poles invented a new method of a double-key crack, which consisted of a set of 26 sheets of paper, each one perforated by 51 by 51 holes. By this method it was possible to find convergent places for the entire set.

But in December 1938, the Germans upgraded their Enigma again, installing two extra rotors to the existing set of three rotors. The Poles could still read the German messages but the effort required to do so was greatly increased: the Poles needed sixty instead of six cryptologic bombs, and sixty paper sheet sets, making the task laborious and cumbersome.

The major difficulty facing the Polish cryptologists was the exchange of a key system of the German army, which took place on July 1, 1939. Between July 24 and 26, 1939,the Polish team met with their French and British counterparts in Warsaw. War was imminent. With the authorization of Polish General Waclaw Stachiewicz, the Polish team presented perfect working copies of a Polish-made clones of the Enigma machine - to the French and British teams.

On 16 August 1939, General Stewart Menzies was given a copy of an Enigma at the Victoria Station in London. The British began to read Enigma messages in mid-August, 1939. That the Allies knew about Germany's position and strength along Polands borders was entirely attributed to the Polish success in decryptment of German Enigma messages.

German Army in Warsaw
When the German armies invaded Poland on September 1st, 1939, they advanced rapidly towards Warsaw. Before they were even able to reach the capital city, all personnel of the Ciphers Office and ELINT surveillance stations, including Rajewski and his colleagues had already fled and escaped to Romania. Rejewski, Rozycki and Zygalski managed to avoid being forced into a refugee camp. Upon reaching Bucharest, they made an attempt to obtain assistance from the British Embassy but it proved unsuccessful. The French Embassy however did provide the Poles with assistance, and they were evacuated, reaching Paris by the end of September.

Soviet Infantry Invading Poland
When the Soviet Union invaded Poland on the 17th of September, 1939, the Ciphers Office received an order from Polish Command to immediately destroy all documentation on the Enigma, and equipment.

A joint Polish-French Intelligence Center was established in October 1939 at the Chateau de Vignolles,in Gretz-Armainvillers, 40 kilometers north-east of Paris, and given the code name "Bruno". The center monitored and intercepted German radio transmissions and was equipped with a teletype link to the Government Code and Ciphers School in England. In addition, Spanish code breakers were also employed at Bruno to decipher Spanish and Italian codes. All messages were relayed to London's Bletchley Center. The information gathered by "Bruno" provided the Allies with invaluable details concerning German operations and communications systems, reports about German agents and the instructions that were given to them, as well as intelligence reports that the Germans were collecting about Allied operations. Also discovered were the orders of battle. Over 287 radio transmissions were intercepted in a matter of a few months, deciphered and relayed to counter-intelligence.

Amid the volume of messages, the Poles were able assess the routine of the German Army Signals Corps that was transmitted every day, just prior to 2400 hours. It provided vital information such as German call signs, wavelengths, and hours of operation. The Germans were systematic and transmitted situation reports in the morning, noon, afternoons, and evenings in addition to intelligence reports, logistic reports, orders, and other official business. Amid those transmissions the Poles also assessed false messages designed by the Germans to deceive the Allies efforts'.

The Polish team kept frequent communication with the Polish Commander-in-Chief in London. Assignments were received and reports sent, sometimes even using the Enigma machine, and ending with the message “Heil Hitler!" (the Poles enjoyed secretly mocking the enemy).

The most important work of the Center was in alerting the Allies about the impending invasion of France by German forces. In May 1940, Germany invaded France and by mid-June had entered Paris. On June 10th, the Bruno unit was ordered to evacuate. France surrendered on June 22nd, and within 48 hours Rejewski and his colleagues had fled and were on their way to Algeria.

Henryk Zygalski en route to Algeria
 The Cadix unit opened a secret branch in the Kouba Villa, a suburb of Algiers, that was headed by Major (later Maj-Gen) M.Z. Rygor-Slowiskowski, the Polish II Directorate's officer. By mid-July the unit was already in full operation decoding secret German messages. A large proportion of intelligence gathered by his unit were instrumental to the Allies, in particular to the Allies "Operation Torch" (North Africa landing).

Incidentally, the Kouba branch (otherwise known as the PO-1 branch) encrypted their messages using a Polish-made LCD enciphering machine (aka "Lacida") which consisted of a modified Remington typewriter with enciphering rotors.

The Polish cyrptologists had enlisted into the Polish Armed Forces Branch "300" of the II Directorate and were soon to make a hazardous journey back into Nazi-occupied France. According to a secret agreement between the Polish and Free French governments, the Poles were to continue their decoding work underground, in the town of Fouzes, near Nimes, France. To alleviate any suspicion, Rejewski posed himself as a mathematics professor from a lycee in Nantes. He worked at the secret intelligence base at Chateau des Fouzes, along with his colleagues decoding German messages.

By October 1940, the new secret unit was dubbed, "Cadix" and it succeeded the Bruno center. The secret German messages they deciphered included the following:

German military orders to their troops throughout Europe and in Libya.
SS and Police messages from Europe.
Spy radio communications among German field agents in Europe or in Libya and 
Abwehr HQ in Stuttgart.
Diplomatic communications and German Armistice
Commission communications in Wiesbaden and their branches in France and in North Africa.

Add captionPolish-French-Spanish Cadix center. From left: 1. Henri Braquenié. 2. Piotr Smoleński. 3. Edward Fokczyński. 5. Maksymilian Ciężki. 7. Gwido Langer. 8. Mary Bertrand, wife of: 9. Gustave Bertrand. 13. Henryk Zygalski (in back, wearing glasses). 14. Jan Graliński. 18. Jerzy Różycki. 20. Marian Rejewski.

Unfortunately, on January 9th, 1942, Jerzy Rozycki died  in tragic circumstances when the M/S "Lamoriciere" he was traveling in, sunk near the Balearic Isles.

In November of the same year, while the Allies launched their invasion of North Africa, the German troops had already occupied Vichy France. The secret undercover unit at the Château des Fouzes was in imminent danger and had to be evacuated. All personnel managed to escape on November 9th just in time. Three days later the Germans discovered the secret operation.

Rejewski and Zygalski embarked on a perilous journey through many cities in southern France and thereby were able to evade capture. Eventually they decided to cross the Pyrenees to reach Spain but en route, they were robbed at gunpoint by their guide. Subsequently, the Poles were arrested and detained at the prison at Seo de Urgel from January to March 1943, then transferred to a prison in Lerida. Finally on May 24, they were released and sent to Madrid from where they continued their journey towards to Portugal and then to Gibraltar by Royal Navy ship. From there they were flown to Britain and landed safely on August 3rd, 1943. Rejewski enlisted in the Polish Army in Britain and remained there for the remainder of the war years, continuing his work on decoding.

Apparently, the British authorities had limited knowledge or understanding of the vast capabilities of Rejewski's genius and did not assign him to Bletchley Park to collaborate on decoding operations. Instead, the Poles were relegated to work at the Radio Battalion at Stanmore Boxmoor, near London, as part of the Polish Army Signals Corps, Polish Armed Forces Branch "300" of the II Directorate. Despite the snub, the Poles continued working and met with success yet again, in cracking the German SS formations cipher.
Cryptanalysts Hut No. 3 Bletchley Park, 1943

The British had initially attempted to break the Enigma code but failed at each attempt. It was only with the collaboration of French and Polish teams, that Britain able to begin cracking codes up to 83% of the codes out of a total of 126 Enigma keys.

From 1940 to 1945 the Polish success rate skyrocketed - from decoding a mere few hundred messages to over 9,000 messages.

During the six years between January 1933 and September 1939, it has been estimated that the Poles were able to decipher approximately 100,000 transmissions, among which dealt with secret information about the remilitarization of the Rhein Province, Anschluss of Austria and seizure of the Sudetenland.

Throughout the war the Polish success at cracking the Enigma Code was kept under the highest degree of security, even within the ranks of the Polish General Staff's II Directorate. Decoded messages were submitted to Polish Officers signed with the code-name "Wicher" ensuring that the source was classified and completely reliable.

After the war, in November 1946 Rejewski returned to Poland, reuniting with his wife and children, and settling in Bydgoszcz with their parents. Rejewski chose not to resume his position as a mathematician at Poznan University though it was his for the taking if he wished to do so. Instead he accepted a job as a supervisor of sales at Polish Cable.

Shortly after his return to Poland, Rejewski suffered the tragic loss of his eleven year old son, from polio. In the ensuing years, their lives became exceedingly difficult by the constant surveillance and enquiries made by the Polish Security Service. Surprisingly, the Security Service was never capable of discovering the role and extent of Rejewski's involvement in deciphering the Enigma Code.

Irregardless,they applied considerable pressure on management officials, and succeeded in getting Rejewski fired from his position in 1950. Thereafter, he worked at a variety of different jobs before finding a bookkeeping position at the Provincial Union of Labour Cooperatives in 1954, where he continued to work until his retirement in 1967.

Two years later, Rejewski and his family relocated to Warsaw. The secret of his work with the Enigma cipher had been carefully safeguarded all these years. In 1973 the truth was finally revealed to the public. It led to a flurry of newspaper articles, radio and television programmes which launched his fame.
He spent the rest of his life writing numerous technical articles on the subject.

He died of a heart attack on February 13, 1980 at the age of 74 and was buried will full military honours.

2005 - Military ceremony commemorating the centennial of Rejewski`s Birth 

Unveiling in 2005 of  Memorial to Rejewski in Bydgoszcz.

2007 Bronze monument erected to honour the three cryptologists, - next to Poznań Castle

Flag of Armia Krajowa (Polish Home Army)


N.B. Sources and other references will be provided at the completion of this special series.


  1. Why is Turing given so much credit for breaking enigma?

    1. Good question. Turing was indeed a brilliant mathematician and cryptologist and developed computer science, the forerunner of the modern computer. British pride in this great achievement is understandable, but it overshadowed the fact that the Poles were the ones to crack the Enigma code. The contributions made by Poles during WW2 were invaluable to the allied war efforts, but were ultimately ignored for the sake of cultivating good relations with Stalin. The reason was political.

  2. The credit Turing received for breaking Enigma is perfectly legitimate, provided this credit is shared with the other actors of this remarkable effort. I agree with "Polish Greatness"' answer: Much of the Polish efforts in WW2 were silenced, as was the Katyn massacre, to comply with Soviet interests. Among Western leaders during WW2, only De Gaulle really cared about Poland (which he knew since 1921), yet he was only a minor partner.
    Also note that Turing himself remained perfectly unknown for decades, until the Enigma story became publicized. Greetings from Paris.