Of all the Allied weaponry and equipment, there was nothing more crucial than the top-secret British project called Ultra. Its mission was to intercept and decipher coded messages sent by the Germans. The catch was, the Germans were using the most challenging code ever developed, appropriately named Enigma.


The Enigma was meant to be the Nazis’ ultimate weapon. It was a cypher machine, designed to produce the ultimate code. Inside it was a system of electrically connected revolving drums, on which letters of the alphabet were placed. When a letter was typed, it was assigned a random letter value. F. W. Winterbotham, one of the founders of Ultra, described the Enigma like this:

A typewriter fed the letters of the message into the machine, where they were so proliferated by the drums that it was estimated a team of top mathematicians might take a month or more to work out all the permutations necessary to find the right answer for a single cypher setting; the setting of the drums in relation to each other was the key which both the sender and receiver would no doubt keep closely guarded. (Winterbotham, 11)
With Enigma at their disposal, the German submarines were able to sink devastating amounts of Allied shipping between 1940 and 1942. Top secret plans were freely sent through Enigma. They were totally confident that the Enigma code could not be broken.


After the Nazis created their invincible cypher machine, they proceeded to mass-produce them in 1938. A Polish mechanic carefully kept track of the parts of the Enigma he was making. From this, he was able to discover that the Nazis had been working on their cypher machine. He got word to the British through the Polish Secret Service, and the British managed to smuggle one out of Poland.


Marian Adam Rejewski [ˈmarjan reˈjefski] ( listen) (16 August 1905 – 13 February 1980) was a Polish mathematician and cryptologist who in 1932 solved the plugboard-equipped Enigma machine, the main cipher device used by Germany. The success of Rejewski and his colleagues Jerzy Różycki and Henryk Zygalski jump-started British reading of Enigma in World War II; the intelligence so gained, code-named “Ultra“, contributed, perhaps decisively, to the defeat of Nazi Germany.(Note 1)

While studying mathematics at Poznań University, Rejewski had attended a secret cryptology course conducted by the Polish General Staff‘s Biuro Szyfrów (Cipher Bureau), which he joined full-time in 1932. The Bureau had achieved little success reading Enigma and in late 1932 set Rejewski to work on the problem. After only a few weeks, he deduced the secret internal wiring of the Enigma. Rejewski and his two mathematician colleagues then developed an assortment of techniques for the regular decryption of Enigma messages. Rejewski’s contributions included devising the cryptologic “card catalog,” derived using his “cyclometer,” and the “cryptologic bomb.”

Five weeks before the German invasion of Poland in 1939, Rejewski and his colleagues presented their results on Enigma decryption to French andBritish intelligence representatives. Shortly after the outbreak of war, the Polish cryptologists were evacuated to France, where they continued their work in collaboration with the British and French. They were again compelled to evacuate after the fall of France in June 1940, but within months returned to work undercover in Vichy France. After the country was fully occupied by Germany in November 1942, Rejewski and fellow mathematicianHenryk Zygalski fled, via SpainPortugal and Gibraltar, to Britain. There they worked at a Polish Army unit, solving low-level German ciphers. In 1946 Rejewski returned to his family in Poland and worked as an accountant, remaining silent about his cryptologic work until 1967.

From this, the British Secret Service were able to understand how Enigma worked, but were unable to break the code. They set up headquarters at Bletchley Park, along with dozens of expert mathematicians, cryptographers, and even chess champions. Teamed with the best computer technology at the time, these cryptographers were responsible for solving the Enigma. They would spend months analyzing the code, trying to unlock its secret. It was an incredible strain, and some of them suffered nervous breakdowns trying to solve it. But with millions of lives at stake, they knew they had no choice. They would either break the enigma code, or witness a German victory.

However, in 1940, what seemed like the impossible finally happened. A few practice messages sent by the Germans in Enigma code were intercepted and deciphered. Although the actual contents of the messages were totally useless, Enigma had been solved. From this point on, the British were able to decipher the German messages one after another. To distinguish themselves from other cypher teams, the British team called itself Ultra.

Ultra was one of the most carefully kept secrets of World War Two. Only the people actually working with it knew of its existence. If the Germans found out that Enigma had been deciphered, they would change the code. Solving it once had been nightmare enough. Ultra did not want to go through it again.

For two years, Ultra proved itself to be vital to the Allies time and time again. Without it, the Allies would never have been able to win the war. During the Battle of Britain, Ultra saved Air Marshal Dowding and the Royal Air Force from defeat at Goering’s hands. Ultra intercepted German submarine transmissions, which revealed their locations, enabling Ultra to warn Allied vessels. In that same way, Ultra uncovered plans for Operation Sea Lion, a German invasion of Britain. Ultra Intelligence informed General Auchinlek, commander of the Allied forces in North Africa, of General Rommel’s position. This allowed Auchinlek to fight Rommel and the Afrika Korps by hitting them where they were the weakest. Eventually, Auchinlek stopped Rommel before he was able to enter Egypt. Otherwise, the Germans would have had total control of the Mediterranean (Winterbotham, 25).


By February 1944, Ultra had worked with several Allied commanders, including Generals Eisenhower, Montgomery, and Patton-who used Ultra intelligence to “bust open the enemy every chance he had (Winterbotham, 122-123). This cooperation was essential to carrying out the Normandy invasion successfully.

In March 1943, Ultra discovered Hitler’s plans for a secret weapon in the works called the V1 flying-bomb (what they found out about it, such as location of the test-sites and results, has not been revealed yet). By April 1944, Hitler was preparing launch sites on the French coast. Ultra intercepted Hitler’s orders about establishing a headquarters near Amiens to control the V1 operation. The headquarters was named the 155th Flak Regiment. Colonel Siegfried Freiherr von Watchel was in command. That meant that “Overlord,” the Normandy invasion, had to take place as soon as possible (Winterbotham, 119-121).

In May 1944, Ultra intercepted a message from Watchel to General Heinemann, commander of the LXVI Corps (and administrator of the V1 headquarters), saying that fifty sites on the French coast were ready. That meant the Allied attack could not take place any later than June. It was a smart move. On June 6th, D-Day, Watchel was ordered to launch an all-out offensive with the V1s on June 12 (Winterbotham, 121).

A dispute between Hitler and his top generals, during the spring of 1944, would end up providing the most important clue about the German defenses at Normandy. Rommel wanted his panzer divisions directly behind the beach defenses. Hitler, who trusted Rommel’s judgement, went with his recommendation. But another general, Heinz Guderian, felt that the panzers would be wasted on the beaches. Hitler began to grow uncertain and suggested that the two generals talk it out. Guderian was backed up by General Geyr von Schweppenberg, who commanded the panzer group in France. Rommel adamantly refused to give in. He sent a message to Hitler, reinforcing his plans to have the panzer division behind the Normandy beaches. He felt that the superior Allied air power would severely hamper the movement of the tanks (Winterbotham, 125-127).

This gave everything away to Ultra. Rommel’s message revealed the locations of the panzer division on the Normandy beaches. Although Ultra did not receive Hitler’s response, now they knew what to be on the lookout for. Schweppenberg gave even more away when he personally asked Hitler to keep a majority of the panzers near Paris. Hitler’s response (which was intercepted by Ultra this time) was to keep four divisions, the reserve forces, would remain where they were, as an assault force. This made Overlord easier for the Allies. If Hitler had moved these divisions to the beach, the Germans would have overwhelmed the Allies at Normandy (Winterbotham, 127-128).

Ultra set the stage for the Allied victory in Normandy. They had done their part. Now it was the soldiers’ turn.

Works Cited

Winterbotham, F.W. The Ultra Secret. Harper and Row: New York, 1974

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