The Enigma machine used a series of rotor wheels to encode messages
The breaking of the German Enigma code has been cited as one of the major factors that helped win World War II for the Allies.
Two of the Enigma machines used to send and receive coded messages were based at the Naval Signals HQ in St Peter Port.
German Occupation Museum Director Richard Heaume said it was particularly used to communicate with U-Boats.
The code was eventually broken at Bletchley Park near Milton Keynes.
Richard said 7,000 people were employed at Bletchley Park to help break the code and it was when a machine was captured from a German U-Boat that the Allies began to be able to decipher the transmissions.
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He added that the German forces, including the naval commander in Guernsey, "had no idea their codes had been deciphered", and even by 1980 the officer in command of signals in Guernsey did not believe the code could have been broken.
Richard explained that it was only since 1980 that all the information about Bletchley Park's role in decoding Enigma, and how it had affected the outcome of the war, had come to light.
He said "it really won us the war" as once Enigma was decoded the number of German vessels the Allies were able to sink soon overtook the number of Allied ships the Germans could sink.
One of the surviving Enigma machines is housed at Guernsey's German Occupation Museum, and though it is not known whether it was one of the ones based in the island, it matches the description and type of the two used in Guernsey.
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