The Enigma machine was a complex encryption device used by the Germans during World War II. A flaw in its design made it possible for the British to crack the code. The flaw was that a letter could never become itself when encrypted. The British used this flaw to their advantage by trying to find a phrase that would likely be in a message, such as a weather report, and then using that phrase to figure out the settings of the Enigma machine. They built a machine called the Bombe, designed by Alan Turing, which helped to crack the code by process of elimination. The Bombe machine was able to check all possible rotor positions in about 20 minutes, allowing the British to decipher the encrypted messages. The Enigma machine's makers could have avoided this problem by making it possible for a letter to become itself when encrypted, but they did not. The British actually created their own version of the Enigma machine, called the Type X machine, which did allow for a letter to become itself and was deemed more secure by the Germans.
1. The Enigma machine has a feature where a letter cannot become itself in the coded message.
2. Every morning at 6 o'clock, the Germans would send a weather report in a standard format.
3. The British codebreakers used the standard weather report format to help break the Enigma code.
4. The bombe machine was designed by Alan Turing and Gordon Welchman to help break the Enigma code.
5. The bombe machine could break the Enigma code in under 20 minutes.
6. The Enigma machine settings changed every morning at midnight.
7. The plugboard on the Enigma machine connected letters in pairs.
8. The signal on the Enigma machine went through the plugboard, then the rotors, and then the plugboard again.
9. The bombe machine worked by a process of elimination to find the correct settings for the Enigma machine.
10. The bombe machine was named after a Polish codebreaking machine called "bomba".
11. The Polish "bomba" machine was a different machine that worked on a different principle.
12. The Germans used a different code to send the rotor starting positions for naval Enigma codes.
13. The British developed a machine called the "type X" machine, which did not have the flaw of the Enigma machine.
14. The Germans tried to break the British "type X" code but gave up, concluding it was more secure than the Enigma machine.