Changes

Decryption required an understanding of how Enigma functioned, the wiring of the rotors and the daily settings (both rotors and plugboard).

Decryption required an understanding of how Enigma functioned, the wiring of the rotors and the daily settings (both rotors and plugboard).

Nazi Germany used the Enigma before and during World War II to send messages about its military maneuvers.  But in 1932 a 27-year-old Polish mathematician (cryptologist) named Marian Rejewski had used advanced mathematics (permutation theory with some group theory) to secretly break ("crack") the Enigma codes.  He then helped design working "doubles" of the Enigmas that could find the keys necessary for decryption.  By 1938 the Poles were decrypting most of the German messages, and the Poles shared their marvelous discovery with Great Britain and France.

Nazi Germany used the Enigma before and during World War II to send messages about its military maneuvers.  But in 1932 a 27-year-old Polish mathematician (cryptologist) named Marian Rejewski had used advanced mathematics (permutation theory with some group theory) to secretly break ("crack") the Enigma codes.  He then helped design working "doubles" of the Enigmas that could find the keys necessary for decryption.  By 1938 the Poles were decrypting most of the German messages. However, the Poles were forced to share their codebreaking techniques with Great Britain and France after the Germans brought in a new variant on Enigma that made it haredr to decipher.

 

Following the German invasion of Poland work on breaking the Enigma codes moved to France and Great Britain. French efforts were ended by the Fall of France in 1940, but in Great Britain Enigma was finally cryptographically broken thanks to the work done by code-breaking experts in the secret Bletchley Park facility, where some of the earliest and crudest computers were built to work on the millions of code combinations used by Enigma.

The breakthrough enabled the Allies to anticipate German military maneuvers, although sometimes the Allies would allow an attack to occur successfully in order to avoid signaling to the Germans that their code had been broken.  The [[Allied]] code-breaking effort was known as "Ultra", as in "ultra-secret".

The breakthrough enabled the Allies to anticipate German military maneuvers, although sometimes the Allies would allow an attack to occur successfully in order to avoid signaling to the Germans that their code had been broken.  The [[Allied]] code-breaking effort was known as "Ultra", as in "ultra-secret".