Decrypting Code: In 1937, Turing became interested in decrypting code and cryptography. The first thing that he came up with was a device called the electronic multiplier. It was used for code which multiplied binary numbers and patterns by the second code (binary was the first). The only way to understand what the message was saying was by using the decrypted code and using the second code to put it back into binary, to then figure out what the message was saying. The only way someone would be able to understand what the message was is to know what the second code was. After he made the idea, he went into Princeton's machine shop and made his idea, which worked. In 1938, he received a doctoral degree from Princeton and then went back to England.
In 1938, he started to work for the Government Code and Cipher School. After a year, in 1939, he then moved to Bletchley Park and worked there for the same company. His job was to try to figure out a way to decode German messages during World War II. His job was very hard because the Germans made and used an Enigma machine, so it was nearly impossible to decode. Turing actually made a mathematical way to decode messages faster. They ended up decoding way more messages to figure out what the German's were doing and that helped out the war tremendously for the Allies.
When there wasn't enough workers, they hired many women to help out. Turing was then in charge of supervising them. He then met a girl named Joan Clarke that he liked and had lots of fun with, so he asked her to marry him and she said yes. Sadly for Joan, he couldn't marry her because his sexual orientation was still different than most and he didn't like her in a sexual way.
In 1942, Turing went back to the U.S. because they needed help with decoding the Enigma in Washington DC. Many U.S. cargo ships were being sunk by Germany's U-boats. The U.S. needed to figure out where the U-boats were going to try to stop them, but the only way to know where they would be, would be to decode the Enigma messages. Turing went over and helped the U.S. and turned the war around in the Atlantic Ocean because the U.S. could start striking the U-boats and stop being attacked.
After his help was no longer needed, he went back to Bletchley Park in 1943 to start to work on voice encryption. He worked on that project alone because he liked to work alone better. He then moved ten miles north to a new facility called Hanslope Park. There, he continued to work on his project which he named Delilah. Donald Bayley was an electrical engineer who became good friends with Turing and helped him with Delilah. In 1944, they successfully got the machine to work, but there was no use for it because the war was almost over and it was not good for long distance communications. Then in 1945, after the war ended, Turing was honored with the Order of the British Empire because of his help during the war. After the war was over and there was no need to work on codes anymore, he went to the National Physics Laboratory to continue his old work.
This is a picture of the Bombe Turing used to decode German messages during World War II.