Editing World War II cryptography (section)

{{Short description|Military code use and breaking during the Second World War}}
'''Cryptography was used extensively during World War II''' because of the importance of radio communication and the ease of [[Listening station|radio interception]]. The nations involved fielded a plethora of [[code (cryptography)|code]] and [[cipher]] systems, many of the latter using [[rotor machine]]s. As a result, the theoretical and practical aspects of ''[[cryptanalysis]]'', or ''codebreaking'', were much advanced.

Possibly the most important codebreaking event of [[World War II|the war]] was the successful decryption by the Allies of the German [[Cryptanalysis of the Enigma|"Enigma" Cipher]].  The first [[cryptanalysis|break]] into Enigma was accomplished by [[Cipher Bureau (Poland)|Polish Cipher Bureau]] around 1932; the techniques and insights used were passed to the French and British Allies just before the outbreak of the war in 1939. They were substantially improved by British efforts at [[Bletchley Park]] during the war. Decryption of the [[Cryptanalysis of the Enigma|Enigma Cipher]] allowed the Allies to read important parts of German radio traffic on important networks and was an invaluable source of [[military intelligence]] throughout the war. Intelligence from this source and other high level sources, such as  [[Cryptanalysis of the Lorenz cipher]], was eventually called [[Ultra (cryptography)|Ultra]].<ref>{{Cite book|url=https://books.google.com/books?id=uccLlgJDk4gC&q=World+War+II+cryptography|title=Battle of Wits: The Complete Story of Codebreaking in World War II|last=Budiansky|first=Stephen|date=2000|publisher=Simon and Schuster|isbn=9780684859323|language=en}}</ref><ref>{{Cite book|url=https://books.google.com/books?id=j1MC2d2LPAcC&q=World+War+II+codebreaking|title=Codebreakers: The Inside Story of Bletchley Park|last1=Hinsley|first1=F. H.|last2=Stripp|first2=Alan|date=2001|publisher=Oxford University Press|isbn=9780192801326|language=en}}</ref><ref>{{Cite book|url=https://books.google.com/books?id=99oqAwAAQBAJ&q=World+War+II+codebreaking|title=Codebreakers' Victory: How the Allied Cryptographers Won World War II|last=Haufler|first=Hervie|date=2014|publisher=Open Road Media|isbn=9781497622562|language=en}}</ref>

A similar break into the most secure Japanese diplomatic cipher, designated [[Type B Cipher Machine|Purple]] by the US Army Signals Intelligence Service, started before the US entered the war. Product from this source was called [[Magic (cryptography)|Magic]].

On the other side, [[German code breaking in World War II]] achieved some notable successes cracking British naval and other ciphers.