The Enigma 'typewriter'
In 2001, the release of the feature film Enigma sparked great interest in the tweedy world of the boffins who broke Nazi Germany's secret wartime communications codes. But not all who watched Dougray Scott in the film's lead role realised that the title referred to a machine like a typewriter, which encrypted secret messages.
Fewer people still knew that this piece of spook hardware was invented by a German (based on an idea by a Dutchman), that information about it was leaked to the French, and that it was first reconstructed by a Pole, before it was offered to Britain's codebreakers as a way of deciphering German signals traffic during World War Two. As a result of the information gained through this device, it has been claimed, hostilities between Germany and the Allied forces were curtailed by two years.
The importance of signals intelligence became evident during World War One ...
The importance of signals intelligence became evident during World War One, as staff in the British Admiralty's Room 40, under Captain Reginald 'Blinker' Hall, worked at intercepting German communications.
Among these, famously, was the Zimmermann telegram - a message from the German foreign minister to his ambassador in Mexico City informing him of plans to invade the United States. On being notified of these plans, officials in Washington were understandably perturbed, and hastened to effect the entry of the US into the war.
Stealing secrets
After the Treaty of Versailles in 1919, the German defence establishment was eager to improve its compromised communications system, and recognised the potential of a signalling device that had originally been made for the business market.
Dr Arthur Scherbius had developed his 'Enigma' machine, capable of transcribing coded information, in the hope of interesting commercial companies in secure communications. In 1923 he set up his Chiffriermaschinen Aktiengesellschaft (Cipher Machines Corporation) in Berlin to manufacture this product, and within three years the German navy was producing its own version, followed in 1928 by the army and in 1933 by the air force.
... a German spy ... allowed his French spymasters to photograph stolen Enigma operating manuals
Enigma allowed an operator to type in a message, then scramble it by means of three to five notched wheels, or rotors, which displayed different letters of the alphabet. The receiver needed to know the exact settings of these rotors in order to reconstitute the coded text. Over the years the basic machine became more complicated, as German code experts added plugs with electronic circuits.
Britain and her allies first understood the problems posed by this machine in 1931, when a German spy, Hans Thilo Schmidt, allowed his French spymasters to photograph stolen Enigma operating manuals, although neither French nor British cryptanalysts could at first make headway in breaking the Enigma cipher.
It was only after they had handed over details to the Polish Cipher Bureau that progress was made. Helped by its closer links to the German engineering industry, the Poles managed to reconstruct an Enigma machine, complete with internal wiring, and to read the Wehrmacht's messages between 1933 and 1938.
Pinching the codes
By then the greatest threat to the Allied war effort came from attacks on their ship convoys in the North Atlantic. As a result, Bletchley's resources were concentrated on breaking Enigma codes used by German U-boats in this sphere of war. If the Allies could find out in advance where U-boats were hunting, they could direct their ships, carrying crucial supplies from North America, away from these danger zones.
So began one of the most exciting periods of Enigma code-breaking. Even in 1940 Bletchley had had some success in breaking Enigma keys used by the German navy.
It soon became clear that the best way of keeping up with rapid changes in ciphers and related technology was to capture Enigma machines and code-books on board German vessels.
In the Admiralty, where the Operational Intelligence Centre (OIC) was a leading user of Ultra, Commander Ian Fleming, Personal Assistant to the Director of Naval Intelligence, showed his talent for fantastical plots when he suggested a plan (known as Operation Ruthless) to crash-land a captured German plane in the English channel, and to overpower the patrol boat that came to rescue its supposed survivors, thereby gaining access to Enigma materials. The plan was never implemented.
... the German trawler Krebs was captured off Norway, complete with two Enigma machines ...
A break-through came in March 1941, however, when the German trawler Krebs was captured off Norway, complete with two Enigma machines and the Naval Enigma settings list for the previous month. This allowed German Naval Enigma to be read, albeit with some delay, in April, by codebreakers at Bletchley.
Around this time, Harry Hinsley, a Bletchley codebreaker, suggested that German weather and supply ships, as well as war ships, probably carried Naval Enigma details. This idea was proved correct when, in May 1941, the German weather ship München was attacked and found with Enigma code-books for June on board.
The capture of the supply ship Gedania and weather ship Lauenburg in June yielded codebooks for the following month, and opened the way to the reading of Naval Enigma almost concurrently with events.
The ambush of three German U-boats off Cape Verde in September, however, coupled with a dramatic fall in the number of Allied ships sunk in the North Atlantic, led the German Admiral Karl Dönitz to question if the navy's cipher had been compromised.
Although he was dissuaded by his experts, the Germans redoubled their efforts to tighten Enigma's security, and the Bletchley Park codebreakers, realising what they were up against, wrote to British Prime Minster Winston Churchill complaining that they were not being given enough resources. Churchill replied with a famous 'Action This Day' memorandum: 'Make sure they have all they want on extreme priority and report to me that this had been done'.
In 2001, the release of the feature film Enigma sparked great interest in the tweedy world of the boffins who broke Nazi Germany's secret wartime communications codes. But not all who watched Dougray Scott in the film's lead role realised that the title referred to a machine like a typewriter, which encrypted secret messages.
Fewer people still knew that this piece of spook hardware was invented by a German (based on an idea by a Dutchman), that information about it was leaked to the French, and that it was first reconstructed by a Pole, before it was offered to Britain's codebreakers as a way of deciphering German signals traffic during World War Two. As a result of the information gained through this device, it has been claimed, hostilities between Germany and the Allied forces were curtailed by two years.
The importance of signals intelligence became evident during World War One ...
The importance of signals intelligence became evident during World War One, as staff in the British Admiralty's Room 40, under Captain Reginald 'Blinker' Hall, worked at intercepting German communications.
Among these, famously, was the Zimmermann telegram - a message from the German foreign minister to his ambassador in Mexico City informing him of plans to invade the United States. On being notified of these plans, officials in Washington were understandably perturbed, and hastened to effect the entry of the US into the war.
Stealing secrets
After the Treaty of Versailles in 1919, the German defence establishment was eager to improve its compromised communications system, and recognised the potential of a signalling device that had originally been made for the business market.
Dr Arthur Scherbius had developed his 'Enigma' machine, capable of transcribing coded information, in the hope of interesting commercial companies in secure communications. In 1923 he set up his Chiffriermaschinen Aktiengesellschaft (Cipher Machines Corporation) in Berlin to manufacture this product, and within three years the German navy was producing its own version, followed in 1928 by the army and in 1933 by the air force.
... a German spy ... allowed his French spymasters to photograph stolen Enigma operating manuals
Enigma allowed an operator to type in a message, then scramble it by means of three to five notched wheels, or rotors, which displayed different letters of the alphabet. The receiver needed to know the exact settings of these rotors in order to reconstitute the coded text. Over the years the basic machine became more complicated, as German code experts added plugs with electronic circuits.
Britain and her allies first understood the problems posed by this machine in 1931, when a German spy, Hans Thilo Schmidt, allowed his French spymasters to photograph stolen Enigma operating manuals, although neither French nor British cryptanalysts could at first make headway in breaking the Enigma cipher.
It was only after they had handed over details to the Polish Cipher Bureau that progress was made. Helped by its closer links to the German engineering industry, the Poles managed to reconstruct an Enigma machine, complete with internal wiring, and to read the Wehrmacht's messages between 1933 and 1938.
Pinching the codes
By then the greatest threat to the Allied war effort came from attacks on their ship convoys in the North Atlantic. As a result, Bletchley's resources were concentrated on breaking Enigma codes used by German U-boats in this sphere of war. If the Allies could find out in advance where U-boats were hunting, they could direct their ships, carrying crucial supplies from North America, away from these danger zones.
So began one of the most exciting periods of Enigma code-breaking. Even in 1940 Bletchley had had some success in breaking Enigma keys used by the German navy.
It soon became clear that the best way of keeping up with rapid changes in ciphers and related technology was to capture Enigma machines and code-books on board German vessels.
In the Admiralty, where the Operational Intelligence Centre (OIC) was a leading user of Ultra, Commander Ian Fleming, Personal Assistant to the Director of Naval Intelligence, showed his talent for fantastical plots when he suggested a plan (known as Operation Ruthless) to crash-land a captured German plane in the English channel, and to overpower the patrol boat that came to rescue its supposed survivors, thereby gaining access to Enigma materials. The plan was never implemented.
... the German trawler Krebs was captured off Norway, complete with two Enigma machines ...
A break-through came in March 1941, however, when the German trawler Krebs was captured off Norway, complete with two Enigma machines and the Naval Enigma settings list for the previous month. This allowed German Naval Enigma to be read, albeit with some delay, in April, by codebreakers at Bletchley.
Around this time, Harry Hinsley, a Bletchley codebreaker, suggested that German weather and supply ships, as well as war ships, probably carried Naval Enigma details. This idea was proved correct when, in May 1941, the German weather ship München was attacked and found with Enigma code-books for June on board.
The capture of the supply ship Gedania and weather ship Lauenburg in June yielded codebooks for the following month, and opened the way to the reading of Naval Enigma almost concurrently with events.
The ambush of three German U-boats off Cape Verde in September, however, coupled with a dramatic fall in the number of Allied ships sunk in the North Atlantic, led the German Admiral Karl Dönitz to question if the navy's cipher had been compromised.
Although he was dissuaded by his experts, the Germans redoubled their efforts to tighten Enigma's security, and the Bletchley Park codebreakers, realising what they were up against, wrote to British Prime Minster Winston Churchill complaining that they were not being given enough resources. Churchill replied with a famous 'Action This Day' memorandum: 'Make sure they have all they want on extreme priority and report to me that this had been done'.