During World War II, Germany believed that its secret codes for radio messages were indecipherable to the Allies. However, the meticulous work of code breakers based at Britain’s Bletchley Park cracked the secrets of German wartime communication, and played a crucial role in the final defeat of Germany.
The Enigma story began in the 1920s, when the German military - using an ‘Enigma’ machine developed for the business market – began to communicate in unintelligible coded messages. The Enigma machine enabled its operator to type a message, then ‘scramble’ it using a letter substitution system, generated by variable rotors and an electric circuit. To decode the message, the recipient needed to know the exact settings of the wheels. German code experts added new plugs, circuits and features to the machine during the pre-war years, but its basic principle remained the same.
The first people who came close to cracking the Enigma code were the Polish. Close links between the German and Polish engineering industries allowed the Polish Cipher Bureau to reconstruct an Enigma machine and read the Wehrmacht’s messages between 1933 and 1938. In 1939, with German invasion looming, the Poles shared their information with the British, who in turn established the Government Code and Cipher School at Bletchley Park in Buckinghamshire. Mathematicians and intelligence experts, with the help of primitive early computers, began the complex and urgent task of cracking the Enigma code.
The Germans, convinced their Enigma messages were unbreakable, used the machine for battlefield, naval, and diplomatic communications. Although the experts at Bletchley first succeeded in reading German code during the 1940 Norwegian campaign, their work only began to pay off meaningfully in 1941, when they were able to gather evidence of the planned invasion of Greece, and learn Italian naval plans for the Battle of Cape Matapan. In the autumn, the Allies gained advantage in North Africa from deciphering coded messages used by Rommel’s Panzer Army. Information obtained from such high-level German sources was codenamed ULTRA.
The Germans also enjoyed some noteworthy code breaking successes. The B-Dienst (surveillance service) broke British Naval code as early as 1935, which allowed them to pinpoint Allied convoys during the early stages of the Battle of the Atlantic. Although the US altered its naval code in April 1942, the change came too late to prevent the havoc wreaked by Operation Paukenschlag, the German U-boat campaign off America’s east coast early that year. The Germans also managed to crack Soviet and Danish code systems. But their efforts – fragmented and divided between rival cryptology departments - lacked the consistent success achieved at Bletchley Park.
From 1941 onwards, Bletchley’s experts focused upon breaking the codes used by German U-boats in the Atlantic. In March 1941, when the German armed trawler ‘Krebs’ was captured off Norway complete with Enigma machines and codebooks, the German naval Enigma code could finally be read. The Allies could now discover where U-boats were hunting and direct their own ships away from danger.
The German Navy, rightly suspicious that their code had been cracked, introduced a fourth wheel into the device, multiplying the possible settings by twenty six. The British finally broke this code that they called ‘Shark’ in December 1942. Using ULTRA always presented problems to the Allies, because any too blatant response to it would cause the Germans to suspect their messages were being read. But nevertheless Bletchley Park and its staff made a crucial and groundbreaking contribution to the defeat of the Axis.
Did you know...
The British tried hard to conceal their code breaking success from the Axis. In 1942, when five Italian ships bound for Africa were sunk due to ULTRA information, Churchill sent a telegram to Naples congratulating a fictitious spy and awarding him a bonus
Code Breakers Finally Crack The Mysterious Cypher On The WWII Carrier Pigeon
A coded message from the Second World War found tied to the remains of a carrier pigeon in a chimney contains details of German tank movements sent by a British soldier, a team of Canadian researchers believe.
The letter was discovered by David and Anne Martin while they were ripping out a fireplace at their house in Bletchingley, Surrey, thirty years ago.
They discovered the bones of a pigeon and were about to throw them away when they noticed there was a red container attached to one of the bird's legs.
It is now believed the message, which had stumped Britain's finest codebreakers, was battlefield intelligence from a British Army paratrooper pointing out German tank and infantry groupings to RAF Bomber Command.
Inside was a small slip of paper with a series of 27 coded messages, made up of a mixture of letters and numbers.
The couple sent it to Colin Hill, curator of the Pigeons at War exhibition at Bletchley Park, but he found the code, believed to have been sent by a unit in Normandy shortly after D-Day to Bomber Command, impossible to crack.
Government Communication Headquarters (GCHQ) in Cheltenham, Gloucestershire, to examined code in November this year. The eavesdropping agency also appealed for former code breakers to come forward to suggest how the code might be understood. Daily Telegraph readers also sent in their suggestions.
But it is a team of Canadian researchers at Lakefield Heritage Research who claim to have cracked the short-form code, using a First World War artillery code book.
The message was sent to XO2 at 16:45 and contained 27 codes, each made up of five letters or numbers.
The destination X02 was believed to be Bomber Command, while the sender's signature at the bottom of the message read Serjeant W Stot.
The message reads:
AOAKN HVPKD FNFJW YIDDC
RQXSR DJHFP GOVFN MIAPX
PABUZ WYYNP CMPNW HJRZH
NLXKG MEMKK ONOIB AKEEQ
WAOTA RBQRH DJOFM TPZEH
LKXGH RGGHT JRZCQ FNKTQ
KLDTS FQIRW AOAKN 27 1525/6
It can now be revealed the message was sent by Sergeant William Stott, a 27-year-old paratrooper from the Lancashire Fusiliers who was parachuted into occupied Normandy on a reconnaissance mission.
It is believed he was sent there to assess the strength of the German occupation in that area, and then sent the message to HQ Bomber Command at RAF High Wycombe.
His message told RAF officers that he was updating as required, and he was also requesting information after being parachuted behind enemy lines early in the morning.
He was killed in action a few weeks after sending the message, which has now been partly decoded by the Canadian research team.
Gord Young, a researcher from Peterborough in Ontario, said: "We have been able to unravel most but not all of the so-called unbreakable code of the pigeon remains.
"The message is indeed breakable."
The researchers now believe the message reads: "Artillery observer at 'K' Sector, Normandy. Requested headquarters supplement report. Panzer attack - blitz. West Artillery Observer Tracking Attack.
"Lt Knows extra guns are here. Know where local dispatch station is. Determined where Jerry's headquarters front posts. Right battery headquarters right here.
"Found headquarters infantry right here. Final note, confirming, found Jerry's whereabouts. Go over field notes. Counter measures against Panzers not working.
"Jerry's right battery central headquarters here. Artillery observer at 'K' sector Normandy. Mortar, infantry attack panzers.
"Hit Jerry's Right or Reserve Battery Here. Already know electrical engineers headquarters. Troops, panzers, batteries, engineers, here. Final note known to headquarters."
Other parts of the code require further deciphering but Mr Young thinks they may be confusing on purpose to dupe German soldiers who may have picked up the letter.
He said: "Maybe these are 'fillers' just to confuse the Germans or anyone else who might have got the message.
"We have written to the Canadian War Museum to see if they can find somebody who understands artillery short forms."
The task was complicated by the fact that all the code books and computers at Bletchley Park, the wartime predecessor to GCHQ, were destroyed after the war.
The Royal Pigeon Racing Association believe the bird probably either got lost, disorientated in bad weather, or was simply exhausted after its trip across the Channel.
Due to Winston Churchill's radio blackout, homing pigeons were taken on the D-Day invasion and released by Allied Forces to inform military Generals back on English soil how the operation was going.
The crack team of birds were a secret wing of the National Pigeon Service - which had a squadron of 250,000 birds during the Second World War.
They can reach speeds of 80mph, cover distances of more than 1,000 miles and are thought to use the Earth's magnetic fields to navigate.