How did the Allies know about the Enigma Machine?

The Allies became aware of the Enigma machine through various intelligence efforts, including the work of Polish cryptanalysts in the early 1930s who first broke its codes. After the German invasion of Poland in 1939, the Polish intelligence shared their findings and the machine itself with British and French officials. This collaboration laid the groundwork for the British codebreakers at Bletchley Park, who further developed techniques to decipher Enigma-encrypted communications throughout World War II.