Open main menu
Home
Random
Recent changes
Special pages
Community portal
Preferences
About Wikipedia
Disclaimers
Incubator escapee wiki
Search
User menu
Talk
Dark mode
Contributions
Create account
Log in
Editing
Ultra (cryptography)
(section)
Warning:
You are not logged in. Your IP address will be publicly visible if you make any edits. If you
log in
or
create an account
, your edits will be attributed to your username, along with other benefits.
Anti-spam check. Do
not
fill this in!
===German=== [[File:Typical Bletchley intercept sheet.jpg|thumb|upright|A typical Bletchley intercept sheet, before decryption and translation]] [[File:Bletchley decrypt.jpg|thumb|upright|A typical Bletchley intercept sheet, after decryption]] ====Enigma==== {{Main|Cryptanalysis of the Enigma}} "[[Enigma machine|Enigma]]" refers to a family of electro-mechanical [[Rotor machine|rotor cipher machines]]. These produced a [[Polyalphabetic cipher|polyalphabetic substitution cipher]] and were widely thought to be unbreakable in the 1920s, when a variant of the commercial Model D was first used by the [[Reichswehr]]. The [[German Army (1935β1945)|German Army]] (''Heer''), [[Kriegsmarine|Navy]], Air Force, [[Nazi Party|Nazi party]], [[Gestapo]] and German diplomats used Enigma machines in several variants. [[Abwehr]] (German military intelligence) used a four-rotor machine without a plugboard and Naval Enigma used different key management from that of the army or air force, making its traffic far more difficult to cryptanalyse; each variant required different cryptanalytic treatment. The commercial versions were not as secure and [[Dilly Knox]] of GC&CS is said to have broken one before the war. German military Enigma was first broken in December 1932 by [[Marian Rejewski]] and the [[Biuro SzyfrΓ³w|Polish Cipher Bureau]], using a combination of brilliant mathematics, the services of a spy in the German office responsible for administering encrypted communications, and good luck.{{sfn|Singh|1999|p=145}}{{sfn|Copeland|2004|pp=231, 232}} The Poles read Enigma to the outbreak of World War II and beyond, in France.{{sfn|Kozaczuk|1984|pp=81β92}} At the turn of 1939, the Germans made the systems ten times more complex, which required a tenfold increase in Polish decryption equipment, which they could not meet.{{sfn|Rejewski|1984|pp=242β43}} On 25 July 1939, the Polish Cipher Bureau handed [[Polish Enigma doubles|reconstructed Enigma machines]] and their techniques for decrypting ciphers to the French and British.{{sfn|Copeland|2004|pp=234, 235}} [[Gordon Welchman]] wrote, {{Quote|Ultra would never have got off the ground if we had not learned from the Poles, in the nick of time, the details both of the German military Enigma machine, and of the operating procedures that were in use.|Gordon Welchman{{sfn|Welchman|1984|p=289}}}} At Bletchley Park, some of the key people responsible for success against Enigma included mathematicians [[Alan Turing]] and [[Conel Hugh O'Donel Alexander|Hugh Alexander]] and, at the [[British Tabulating Machine Company]], chief engineer [[Harold Keen]].<ref name="haigh"/> After the war, interrogation of German cryptographic personnel led to the conclusion that German cryptanalysts understood that cryptanalytic attacks against Enigma were possible but were thought to require impracticable amounts of effort and investment.{{sfn|Bamford|2001|p=17}} The Poles' early start at breaking Enigma and the continuity of their success gave the Allies an advantage when World War II began.{{sfn|Welchman|1984|p=289}} ====Lorenz cipher==== {{Main|Cryptanalysis of the Lorenz cipher}} In June 1941, the Germans started to introduce on-line [[stream cipher]] [[teleprinter]] systems for strategic point-to-point radio links, to which the British gave the code-name [[Fish (cryptography)|Fish]].{{sfn|Gannon|2006|p=103}} Several systems were used, principally the [[Lorenz cipher|Lorenz SZ 40/42]] (codenamed "Tunny" by the British) and [[Siemens and Halske T52|Geheimfernschreiber]] ("Sturgeon"). These cipher systems were cryptanalysed, particularly Tunny, which the British thoroughly penetrated. It was eventually attacked using [[Colossus computer|Colossus]] machines, which were the first digital programme-controlled electronic computers. In many respects the Tunny work was more difficult than for the Enigma, since the British codebreakers had no knowledge of the machine producing it and no head-start such as that the Poles had given them against Enigma.<ref name="haigh">{{cite journal | url=http://cacm.acm.org/magazines/2017/1/211102-colossal-genius/fulltext | first=Thomas | last=Haigh | title=Colossal Genius: Tutte, Flowers, and a Bad Imitation of Turing | journal=[[Communications of the ACM]] | volume=60 | issue=1 | date=January 2017 | pages=29β35 | doi=10.1145/3018994| s2cid=41650745 | url-access=subscription }}</ref> Although the volume of intelligence derived from this system was much smaller than that from Enigma, its importance was often far higher because it produced primarily high-level, strategic intelligence that was sent between Wehrmacht high command ([[Oberkommando der Wehrmacht]], OKW). The eventual bulk decryption of Lorenz-enciphered messages contributed significantly, and perhaps decisively, to the defeat of Nazi Germany.<ref name="Hinsley 1993 8">{{Harvnb|Hinsley|1993a|p=8}}</ref><ref name="Brzezinski 2005 18">{{harv|Brzezinski|2005|p=18}}</ref> Nevertheless, the Tunny story has become much less well known among the public than the Enigma one.<ref name="haigh"/> At Bletchley Park, some of the key people responsible for success in the Tunny effort included mathematicians [[W. T. Tutte|W. T. "Bill" Tutte]] and [[Max Newman]] and electrical engineer [[Tommy Flowers]].<ref name="haigh"/>
Edit summary
(Briefly describe your changes)
By publishing changes, you agree to the
Terms of Use
, and you irrevocably agree to release your contribution under the
CC BY-SA 4.0 License
and the
GFDL
. You agree that a hyperlink or URL is sufficient attribution under the Creative Commons license.
Cancel
Editing help
(opens in new window)