Enigma and Ultra -2

 Later, the Polish army's crypto-decryption unit, which received information from the French Military Intelligence Agency, copied Enigma using design data around December 1932 and began decrypting correspondence for the first time.

(The core of the enigma was on the rotating board. When you press one of the 26 spellings on the Enigma keyboard, the signal reaches the rotating plate through the battery. Each rotating plate is spelled 26 times.Each rotating plate rotates separately, and at this time, light is sent from the top of the machine to the back of the character string. - The letters pressed on the keyboard and the letters receiving the light do not match each other. - The letters receiving the light are transmitted to the other party's Enigma machine, where the other party's Enigma must also be aligned with the one that sends the signal. Germany has created a more improved model by installing a plug connector system with more layers that randomly send electrical signals. Mathematically, the combination of characters possible whenever the enigma was manipulated reached 10 to 21. This process was entirely handled by the machine, and the correspondent simply had to learn how to adjust the keys and change the keys every time the machine was used.)

However, the number of people who decrypt Enigma's code was extremely small, so it was far short of manpower to respond to Germany's various confidentiality measures, such as changing keys and adding rotary boards every day. Furthermore, if one model is solved, Germany will soon create an improved model that enhances security, and in the end, its previous decoding techniques will be useless, and it will have to start all over again. This lasted for seven years, and in December 1938, when Germany added a fifth revolving board to strengthen Enigma's security, the Polish side faced difficulties, and Germany invaded Poland before it could decipher the code completely.

Polish cryptographers who fled to Paris contacted French and British intelligence agencies and handed over copies of the machines and data on their previous decoding operations to Britain. In early 1940, GCHQ moved to a mansion in Bretzley Park near London to escape bombing by the German Air Force, and hired experts from various fields to decode German codes and codes. Among them, Cambridge mathematician Alan Turing improved Polish cryptography machines (Bombes) to a new model that could store information, discovering Enigma's rotation plate combination and cryptography process. Less than a year later, GCHQ decrypted Enigma messages almost as soon as they were sent.

The operation, codenamed Ultra, has since achieved many results. The Royal Air Force Command, which deciphered German bombardment orders throughout the air war in Britain, concentrated its outnumbered fighter jets in major areas to maximize tactical effects and decoded correspondence coordinating attack plans for U-boats and fleets. (But Ultra wasn't perfect.) In 1941, German preparations for an attack on Yugoslavia were detected, but the decrypted ciphertext did not specify the location of the attack, so the British army could not find out. Even during the German western offensive in 1944, the order of attack was delivered only through ground communication, and the Allied Forces were unaware of this.) Communications between senior German officers were exposed for about five years, and all other types of information-related communications were the same, allowing the Allies to grasp the inside of the German intelligence organization. Furthermore, the ultra-system is not only able to decipher communication, but also to check the effective progress of the coalition forces' deception and double espionage operations.

Ernest Volkman : "Espionage", 1995