Figure 1.--

Poles declared their independence in the gfinal days of World War I (October 1918). The borders of the new nation were, however contested by its neigbors, especially Germany and the new Soviet Union. In the West, the League of Nations surpervised referendums, but there were also engagements fought with German militias. In the east there was a full-scale war--the Polish-Soviet War (1919-21). The Polish Cipher Bureau achieved considerable successes cracking Soviet secure communications which ensured the independence of the recently created Polish nation and considerable eastern terrotories. The cracking of the Enigma Machine is perhaps the greatest feat of cryptology and began in Poland nearly two decades before the outbreak of World War II. [Bury] Polish cryptanalysts during the early-1920s had begun intercepting and analyzing German military radio transmissions. Those transmissions suddently became impossible to read, going dark as the cryptologists would put it (February 1926). The Poles had no inside information, but they suspected that the Germans had begun to use encrypted (machine generated) codes. [ Budiansky] At the time the new code seemed impossible to crack. We now know that the Germans had begun using their Enigma machines based on machines developed by the German railways. The Germans had considerable confidence in the security of the transmissions made with the codes generarted by Enigma, largely because of the mathematical complexity. One estimate suggests that the internal rotors of Enigma could be wired to generate a complexity of 10 to the 80th power, meaning 1 followed by an astonishing 80 zeroes. This meant a complexity exponetially greater than ever before faced by code breakers in history. The Polish Cipher Bureau thus began the effort to crack the vaunted German Enigma machines. They managed to do so after Allied intelligence provided them critical information. Right before the outbreak of the War the Germans upgraded their Enigma machine, putting the Poles in the dark. After the German invasion (September 1939), the staff of the Polish Cipher Bureau had to split up and try to make their ways to the West. This became very difficult when the Soviets invaded from the east. Some were killed before reaching safety. Others were captured. None revealed the work of the Cipher Bureau to the Germans. Some managed to reach France where the work on Enigma continued. The Germans remained totally unaware that the Poles had suceeded in penetrating Enigma or even had an important codebreaking effort.

Independence (1918-21)

Poles declared their independence in the gfinal days of World War I (October 1918). The borders of the new nation were, however contested by its neigbors, especially Germany and the new Soviet Union. In the West, the League of Nations surpervised referendums, but there were also engagements fought with German militias. In the east there was a full-scale war--the Polish-Soviet War (1919-21). The Polish Biuro Szyfrów (Cipher Bureau) achieved considerable successes cracking Soviet secure communications which ensured the independence of the recently created Polish nation and considerable eastern terrotories.

Codebreaking

The cracking of the Enigma Machine is perhaps the greatest feat of cryptology and began in Poland nearly two decades before the outbreak of World War II. [Bury] Poland was a relatively small country situated between two giants, the Soviet Union and Germany. Thus the Poles attempted to monitor the military of both countries. Polish cryptanalysts during the early-1920s had begun intercepting and analyzing German military radio transmissions. This was not vunusdual. All of thev major powers and even some smaller countries worked at this. The Biuro Szyfrów proved some of the most successful. I am not entirely sure why this was.

German Enigma Machine (1926-28)

The German military as the basic principles of Blizkrieg began to emerge began upgrading security of their radio communications. World War I offensives often ground to a halt because headquarters often lost contact with advancing combat units. Advances in radio communications meant that fast moving mechanized units could renain in contact with headdquarters. But this meant a much larger volume of communications and the need for time consumin codeing and encoding because all of the radio which were suspectable to enemy interception. The Enigma Machine seemed the perfect solution to the problem. It was a device developed by the German railway system to secure communications. The Germans had absolute confidence in the security of the transmissions made with the codes generarted by Enigma, largely because of the mathematical complexity. One estimate suggests that the internal rotors of Enigma could be wired to generate a complexity of 10 to the 80th power, meaning 1 followed by an astonishing 80 zeroes. This meant a complexity exponetially greater than ever before faced by code breakers in history.

Initial Efforts

The Polish Biuro Szyfrów were surprised when German Naval transmissions suddenly became impossible to read, going dark as the cryptologists would put it (February 1926). The German Army messages went dark (1928). The Poles had no inside information, but they suspected that the Germans had begun to use encrypted (machine generated) codes. [ Budiansky] At the time the new code seemed impossible to crack. We now know that the Germans had begun using their Enigma machines based on machines developed by the German railways. The Biuro Szyfrów as a result began the effort to crack the vaunted German Enigma machines. The Polish team that cracked the Enigma codes was led by Marian Rejewski, Jerzy Rózycki, and Henryk Zygalski. Eventually a vast enterprise of 10,000 people with the first coomputers (bombs) were decoding Axis messages on both sides of the Atantic. These three brilliant Poles with meager resources began the effort and in fact suceeded in cracking Enigma. The understanding they developed would be vital to the activities at Bletchey Park and without thrir work the British would have taken much longer to crack Enigma. Polish agents learned that the Germans as the Biuro Szyfrów suspected were machine encoding their transmissions. The Poles purchased a commercial Enigma machine, but were still unable to decrypt any of the intercepted transmissions.

French Espionage

The break in the Polish effort came through the French Intelligence service (FIS). A german aristocrat, Hans Thilo-Schmidt, was having money problems. His brother, a Lieutenant Colonel in the German signal corps, found him a job. Part of his duties were to destroy old Enigma codes which were no longer valid. He thus became aware of the Enigma machines and how they were operated. And he saw the opportunity to make some serious cash. He approached the French and adopted the code name Asché. He sold FIS agent Gustave Bertrand a booklet detailing the Enigma machine setup procedures. There was, however, no mention of the rotor wiring or information about the the keys. French cryptologisra worked with the information without success. They then shared the booklet with the British who concluded that it was not enough to crack Enigma. The frustrated French decided to approach the Poles, not fully aware of the work at the Biuro Szyfrów

Cracking Enigma

The determinef Bertrand offered the booklet to Marian Rejewski who was astonished to have in his hands actual instructions for Enigma. Rejewski requested thst Bertrand obtain some Enigma keys, even if they were outdated. Schmidt for an additional payment was happy to provide the old keys that he was susposed to destroy. Tghey were soon in Rejewski's hands and the Biuro Szyfrów was hard at work on them.

Wehrmacht Enigma Upgrades (1938-39)

The Munich Crisis (September 1938) looked for a while like war would break out. The German military began preparations for military operations. One of these was to improve security. The Germans began introducing new complications to Enigma thus creating greater problems for any potential codevbreakers. The Poles made some progress in getting back in, but futher German steps given the limited Polish resources effectively froze them out. The Germans had no idea that Enigma had been cracked. This was simply a reasonable precaution on the brink of war. The German upgrades put the Poles in the dark. The Poles did not have the resources to attack the greater complications posed by the German security measures.

Diplomatic Moves (March-August 1939)

The German seizure of Czechoslovakia in total violation of the Munich accor changed everything (March 1939). Even Chamberlain had to admit that Hitler could not be appeased. The British began actively searching for allies for what was now an inevitable war with the Germans. They hoped to sign an agreement with the Soviet Union, but this proved elusive. They did sign an agreenent with the Poles who realized that they were the next NAZI target. The British pledged with the support of France to guarantee Polish independence (March 31, 1939). The key diplmatic move, however, was made by Hitler--the NAZI-Soviet Non-Agression Pact Aigust 23, 1939). Two days after the Non-Agression Pact was signed, Britain and Poland signed a formal Military Alliance (August 25). As a result, just before the Germans struck, the Poles turned over to the British and French copies of their research material and the military Enigma they had built. These materials proved invaluable. Without them the British cryptologists at Bletchely Park would have had to begun their efforts to crack Enigma virtually from scratch and there is o certainty that they woukd have even made a major effort.

German/Soviet Invasion of Poland (September 1939)

Hitler ordered the invasion of Poland, believing the British and French would again back down (September 1, 1939). They did not nd declared war on Germany (September 3). Hitler had not expected this, but he had wanted a war for some time. The Akllies, however, maade no real effort to attack from the West. Well equipped German armies attacked fron the north, west, and south. The out-classed Polish Army fought valiantly, but the Germans rapidy converged on Warsaw. The staff of the Polish Cipher Bureau had to split up and try to make their ways to the West. This became very difficult when the Soviets invaded from the east. Some were killed before reaching safety. Others were captured. None revealed the work of the Cipher Bureau to the Germans. The Germans remained totally unaware that the Poles had suceeded in penetrating Enigma or even had an important codebreaking effort that had already cracked Enigma once.

Operations in France

The code breakers alomg with thousands of others attempted to escape the Germans. Some mamaged to make it to France They had to destroy their equipment in the process. Those that made it were able tocontinue their work in France and shared their results with the British. The British supplied them with with sixty sets of 26 Zygalski sheets. Their sheets had been destroyed in the evacuation.

Fall of France (June 1940)

The fall of France again put the Polish code breakers in danger. The Poles code breakers attemped to reach Britain, but only some made it safely. The Germjans managed to capture most while attempting to cross the Pyrenees into Spain. The Germans had no idea, however, thsat they had captured men who had broken into Enigma. Thus they remained blissfully ignorant that the British were launcjing a major effirt to crack Enigma based on the critical work done by the Poles. None of the Poles ever talked. The British did not use the Poles for the critical work on the Kriegsmarine Schlüssel-M traffic. Bletchley only broke jinto it after naval rotors VI and VII were obtained when a German ship was captured. Jerzy Rózycki was lost at sea while enroute from Algeria to France (January 9, 1942). Henryk Zygalski decided to remain in England after the War. He passed away there in 1978. Marian Rejewski returned to Poland, but a Communist controlled Poland. We do not know if the NKVD ever learned of his work. He died in 1980 aged 74 years.

Sources

Budiansky, Stephen. Battle of Wits: The Complete Story of Codebreaking in World War II

Bury. Jan. "The Greatest Secret of World War II - The Enigma Code Breach".

Created: 1:03 AM 3/12/2011
Last updated: 4:31 AM 3/1/2017