v • d • e The Enigma cipher machine

Enigma machine Enigma rotor details Cryptanalysis of the Enigma Cipher Bureau Perforated sheets Clock Grill Bomba Polish Enigma doubles Cyclometer Bletchley Park Banburismus Herivel tip Bombe Hut 6 Hut 8 PC Bruno Ultra

An Enigma machine rotor.

Ultra (sometimes capitalised ULTRA) was the name used by the British for intelligence resulting from decryption of encrypted German radio communications in World War II. The term eventually became the standard designation in both Britain and the United States for all intelligence from high-level cryptanalytic sources. The name arose because the code-breaking success was considered more important than the highest security classification available at the time (Most Secret) and so was regarded as being Ultra secret. The word Ultra can have several meanings: Ultra was a codename for certain cryptographic intelligence in World War II. Ultra is also the title of a Depeche Mode album. ... Enigma Logo, http://www. ... For a discussion of how Enigma-derived intelligence was put to use, see Ultra (WWII intelligence). ... This article contains technical details about the rotors of the Enigma machine. ... This article or section contains information that has not been verified and thus might not be reliable. ... The Biuro Szyfrów ( (?), Polish for Cipher Bureau) was the Polish agency concerned with cryptology between World Wars I and II. The Bureau enjoyed notable successes against Soviet cryptography during the Polish-Soviet War, helping to preserve Polands independence. ... The method of perforated sheets was a codebreaking technique used against the Enigma machine (see Cryptanalysis of the Enigma). ... The clock, in cryptology, was a method devised by Polish mathematician-cryptologist Jerzy Różycki, at the Polish General Staffs Cipher Bureau, to facilitate decrypting German Enigma messages. ... The grill (Polish: ruszt), in cryptology, was a method used, chiefly early on, by the mathematician-cryptologists of the Polish Cipher Bureau in decrypting German Enigma machine ciphers. ... Cryptologic bomb. ... Diagram of cyclometer, from Marian Rejewski’s papers The cyclometer was a cryptologic device designed by the Polish Cipher Bureau (BS-4) to help decrypt the German Enigma machine during the 1930s. ... During World War II, codebreakers at Bletchley Park decrypted and interpreted messages from a large number of Axis code and cipher systems, including the German Enigma machine. ... Banburismus was a process invented by Alan Turing at Bletchley Park during the Second World War. ... John W. Herivel (born 1918/1919) is a British science historian and former World War II codebreaker at Bletchley Park. ... The Bombe replicated the action of several Enigma machines wired together. ... Hut 6 at Bletchley Park in 2004 Hut 6 was a wartime section of Bletchley Park tasked with the solution of German Army and Air Force Enigma machine ciphers. ... Hut 8 was one of the units at Bletchley Park, the secret British military intelligence operation that opened just before World War II. Led by Alan Turing, Hut 8 was assigned to break the German naval Enigma code. ... PC Bruno was the code name for the intelligence station operated at a farmhouse in the west of France to which French cryptanalysts retired after Paris was captured by the Germans in 1940. ... This article is about algorithms for encryption and decryption. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... Cryptanalysis (from the Greek kryptós, hidden, and analýein, to loosen or to untie) is the study of methods for obtaining the meaning of encrypted information without access to the secret information which is normally required to do so. ...

Much of the German cipher traffic was encrypted on the Enigma machine, hence the term "Ultra" has often been used almost synonymously with "Enigma decrypts". For a discussion of how Enigma-derived intelligence was put to use, see Ultra (WWII intelligence). ... This article or section contains information that has not been verified and thus might not be reliable. ...

Until the name "Ultra" was adopted, there were several cryptonyms for intelligence from this source, including Boniface. For some time thereafter, "Ultra" was used only for intelligence from this channel. A code name or cryptonym is a word or name used clandestinely to refer to another name or word. ...

Group Captain F.W. Winterbotham, in The Ultra Secret (1974), quotes the western Supreme Allied Commander, Dwight D. Eisenhower, as at war's end describing Ultra as having been "decisive" to Allied victory in World War II. Frederick William Winterbotham (1897-1990) was a British Royal Air Force officer who during World War II was responsible for the distribution of Ultra intelligence, gleaned chiefly by decryption of German Enigma machine ciphers at Bletchley Park, fifty miles northwest of London. ... Dwight David Eisenhower, born David Dwight Eisenhower (October 14, 1890 – March 28, 1969), nicknamed Ike, was a five-star General in the United States Army and U.S. politician, who served as the thirty-fourth President of the United States (1953–1961). ...

Sources of ULTRA intelligence

A typical Bletchley intercept sheet, before decryption and translation.

A typical Bletchley intercept sheet, after decryption.

German sources

ULTRA intelligence was largely derived from German cipher traffic. These messages were mostly generated on several variants of an electro-mechanical rotor machine called "Enigma." The Enigma machine was widely thought to be in practice unbreakable in the 1920s, when a variant of the commercial Model D was first used by the German Navy. The German Army, Navy, Air Force, Nazi party, Gestapo, and German diplomats all used Enigma machines, but there were several variants (e.g., the Abwehr 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. Dilly Knox, of GC&CS, is said to have broken it during the 1920s. A series of three rotors from an Enigma machine, used by Germany during World War II In cryptography, a rotor machine is an electro-mechanical device used for encrypting and decrypting secret messages. ... The 1920s is sometimes referred to as the Jazz Age or the Roaring Twenties, usually when speaking about the United States. ... The Kriegsmarine (or War Navy) was the name of the German Navy between 1935 and 1945, during the Nazi regime, superseding the Reichsmarine. ... The German Army (German: [1], [IPA: heɐ]  ) is the land component of the Bundeswehr (Federal Defence Forces) of the Federal Republic of Germany. ...   (German IPA: ) is a generic German term for an air force. ... The Nazi Party, officially: National Socialist German Workers Party, (German: , abbreviated NSDAP), was a political party in Germany between 1919 and 1945. ... The   (contraction of Geheime Staatspolizei: “secret state police”) was the official secret police of Nazi Germany. ... The Abwehr was a German intelligence organization from 1921 to 1944. ... Alfred Dillwyn Dilly Knox (1884–27 February 1943) was a British codebreaker and Greek scholar at Kings College, Cambridge. ... The Government Communications Headquarters (GCHQ) (previously named the Government Code and Cipher School (GC&CS)) is the main British intelligence service providing signals intelligence (SIGINT). ...

After the War interrogation of German cryptographic personnel led to the conclusion that German cryptanalysts understood that cryptanalytic attacks against Enigma were possible but they required immense effort and investment.^[1]

Later in the war, in 1941, the Germans introduced on-line stream cipher teleprinter systems for strategic point-to-point radio links, to which the British gave the generic code-name FISH. Several distinct systems were used, principally the Lorenz SZ 40/42 (initially code-named TUNNY) and Geheimfernschreiber (code-named STURGEON). These cipher systems were also successfully cryptanalysed, particularly TUNNY, which the British thoroughly penetrated. It was eventually attacked using the Colossus, considered to be the forerunner of the electronic programmable digital computer. Although the volume of intelligence derived from this system was much smaller than that derived from Enigma, their importance was high because they produced strategic level intelligence. For other uses, see 1941 (disambiguation). ... The operation of the keystream generator in A5/1, a LFSR-based stream cipher used to encrypt mobile phone conversations. ... Teletype machines in World War II A teleprinter (teletypewriter, teletype or TTY for TeleTYpe/TeleTYpewriter) is a now largely obsolete electro-mechanical typewriter which can be used to communicate typed messages from point to point through a simple electrical communications channel, often just a pair of wires. ... Fish (sometimes FISH) was the Allied codename for any of several German teleprinter stream ciphers used during World War II. While a large number of links were monitored, at least three different encryption systems were distinguished: Tunny — the Lorenz SZ 40/42 from Lorenz Electric. ... The Lorenz machine was used to encrypt high-level German military communications during World War II. British cryptographers at Bletchley Park were able to break the cipher. ... STURGEON exhibit at the National Cryptologic Museum. ... A Colossus Mark II computer. ...

In addition to Enigma and Fish decryptions, ULTRA intelligence was supplemented with material derived from radio communications using different methods, such as radio traffic analysis and direction finding.

Japanese sources - Purple

In the Pacific theater, the Japanese cipher machine dubbed "Purple" by the Americans, and unrelated to the Enigmas, was used for highest-level Japanese diplomatic traffic. It was also cracked, by the US Army's Signal Intelligence Service and disseminated under the codeword MAGIC. Pacific redirects here. ... A fragment of an actual Purple machine found in Berlin at the end of WWII In the history of cryptography, 97-shiki-obun In-ji-ki (九七式欧文印字機) (System 97 Printing Machine for European Characters) or Angooki Taipu B (暗号機B型) (Type B Cipher Machine), codenamed PURPLE by the United States, was... The Signals Intelligence Service (SIS) was the Armys codebreaking division. ...

Some Purple decrypts proved useful elsewhere, for instance detailed reports by Japan's ambassador to Germany which were encrypted on the Purple machine. These reports included reviews of German strategy and intentions, reports on direct inspections (in one case, of Normandy beach defenses) by the ambassador, and reports of long interviews with Hitler.

The Japanese are said to have obtained an Enigma machine as early as 1937, although it is debated whether they were given it by their German ally or bought a commercial version which, except for plugboard and actual rotor wirings, was essentially the German Army / Air Force machine.

Preparation of Ultra summaries

Initially, Army and Air Force related intelligence derived from SIGINT sources (mainly Enigma decrypts) was compiled in summaries at GCHQ (Bletchley Park) Hut 3. The summaries were subsequently distributed under the codeword "BONIFACE", presumably to imply that they were the result of human intelligence operations. The Admiralty (Royal Navy) produced its own intelligence summaries at the RN Operational Intelligence Centre (OIC),^[2] which were distributed under the codeword "HYDRO".^[3] The Government Communications Headquarters (GCHQ) (previously named the Government Code and Cipher School (GC&CS)) is the main British intelligence service providing signals intelligence (SIGINT). ...

In June 1941 new arrangements were made for distribution of Boniface bulletins and from this point on the term "ULTRA SECRET" was used".^[4] The term "Ultra" was reportedly suggested by Commander Geoffrey Colpoys, RN, who served in the RN OIC.

Dissemination of Ultra intelligence

Distribution of Ultra to Army and Air Force

The distribution of Ultra information to Allied commanders and units in the field involved considerable risk of discovery by the Germans, and great care was taken to control both the information and knowledge of how it was obtained. Liaison officers were appointed for each field command to manage and control dissemination.

Dissemination of Ultra intelligence to field commanders was achieved by the MI6, which operated Special Liaison Units (SLU) attached to major army and air force commands. The activity was organized and supervised on behalf of MI6 by Group Captain Frederick William Winterbotham.^[5][6] The SLU included intelligence, communications and cryptographic elements. Each SLU was headed by a British Army officer, usually a major, known as "Special Liaison Officer". The main function of the Liaison Officer or his deputy was to pass Ultra intelligence bulletins to the commander of the command he was attached to, or to other indoctrinated staff officers. In order to safeguard Ultra, special precautions were taken. The standard procedure was for the Liaison Officer to present the intelligence summary to the recipient, stay with him while he studied it and then take it back and destroy it. The Secret Intelligence Service (SIS), more commonly known as MI6 (originally Military Intelligence Section 6), or the Secret Service, is the United Kingdom external security agency. ... Frederick William Winterbotham (1897-1990) was a British Royal Air Force officer who during World War II was responsible for the distribution of Ultra intelligence, gleaned chiefly by decryption of German Enigma machine ciphers at Bletchley Park, fifty miles northwest of London. ...

Fixed SLU's existed at the Admiralty, the War Office, the Air Ministry and RAF Fighter Command. These units had permanent teleprinter links to Bletchley Park.

Mobile SLUs were attached to field Army and Air Force headquarters. These SLUs depended on radio communications to receive intelligence summaries.

The first mobile SLUs appeared during the French campaign of 1940. An SLU supported the British Expeditionary Force (BEF) headed by General Lord Gort. The first liaison officers were Robert Gore-Browne and Humphrey Plowden.^[7] A second SLU of the 1940 period was attached to the RAF Advanced Air Striking Force at Meaux commanded by Air Vice-Marshal P H Lyon Playfair. This SLU was commanded by Squadron Leader F.W. (Tubby) Long. The British Expeditionary Force (BEF) was the British army sent to France and Belgium in World War I and British Forces in Europe from 1939–1940 during World War II. The BEF was established by Secretary of State for War Richard Haldane following the Second Boer War in case the... Field Marshal John Standish Surtees Prendergast Vereker, 6th Viscount Gort VC GCB CBE DSO and two Bars MVO MC (commonly known as Lord Gort) (10 July 1886 - 31 March 1946) was a British soldier who served in both World War I and II, rising to the rank of field marshal... The RAF Advanced Air Striking Force was formed on 24 August 1939 from No. ... Coordinates Administration Country Region Île-de-France Department Seine-et-Marne (sous-préfecture) Arrondissement Meaux Canton Chief town of 2 cantons: Meaux-Nord, Meaux-Sud Intercommunality Communauté dagglomération du Pays de Meaux Mayor Jean-François Copé (2001-2008) Statistics Altitude 39 m–107 m Land area... Air Marshal Sir Patrick Henry Lyon Playfair KBE CB CVO MC RAF (22 November 1889 – 23 November 1974) was a commander in the Royal Flying Corps during World War I and a senior commander in the Royal Air Force until his retirement during World War II. Air of Authority - A...

Distribution of Ultra to intelligence agencies

In 1940 special arrangements were made within the British intelligence services for handling BONIFACE and later Ultra intelligence. The Security Service started "Special Research Unit B1(b)" under Herbert Hart. In the SIS this intelligence was handled by "Section V" based at St. Albans.^[8] MI-5 redirects here. ... The Secret Intelligence Service (SIS), more commonly known as MI6 (originally Military Intelligence Section 6), or the Secret Service, is the United Kingdom external security agency. ...

Radio communications and cryptography

The communications system was founded by Brigadier Sir Richard Gambier-Parry, who was Head of MI6 Section VIII from 1938 to 1946 and was based at Whaddon Hall in Buckinghamshire, UK.^[9]. Ultra summaries from Bletchley Park were sent over landline to the radio transmitter site of Section VIII at Windy Ridge. From there they were transmitted over radio to the destination SLU.

The communications element of each SLU was called "Special Communications Unit" or SCU. Radio transmitters were constructed at Waddon Hall workshops, while receivers were the National HRO, made in the USA. The SCU's were highly mobile and the first such units used civilian Packard cars. The following SCUs are listed:^[9] SCU1 (Whaddon Hall), SCU2 (France before 1940, India), SCU5, SCU6 (possibly Algiers and Italy), SCU7 (training unit in the UK), SCU8 (Europe after D-day), SCU9 (Europe after D-day), SCU11 (Palestine and India), SCU12 (India), SCU13 and SCU14. ^[10]

The cryptographic element of each SLU was supplied by the RAF and was based on the TYPEX cryptographic machine and one time pad systems. Typex was based on the commercial Enigma machine, but incorporated a number of additional features to improve the security. ... In cryptography, the one-time pad (OTP), is a theoretically unbreakable method of encryption where the plaintext is combined with a random pad the same length as the plaintext. ...

The RN Ultra messages from the RN OIC to ships at sea were necessarily transmitted over normal naval radio circuits and were protected by one time pad encryption. ^[11] In cryptography, the one-time pad (OTP), is a theoretically unbreakable method of encryption where the plaintext is combined with a random pad the same length as the plaintext. ...

Lucy

An intriguing question concerns alleged use of Ultra information by the "Lucy" spy ring. This was an extremely well informed, and rapidly responsive, ring which was able to get information "directly from the German General Staff Headquarters"—often on specific request. It has been alleged "Lucy" was, in major part, a way for the British to feed Ultra intelligence to the Soviets in a way that made it appear to have come from highly-placed espionage and not from cryptanalysis of German radio traffic; this is in some doubt, because the Soviets (via an agent in Bletchley, John Cairncross) knew Britain had broken Enigma. The Lucy Ring was operated, apparently, by one man, Rudolf Roessler, and was initially treated with considerable suspicion by the Soviets. The information it provided was accurate and timely, and Soviet agents in Switzerland (including Alexander Rado, the director) eventually took it quite seriously. In World War II espionage, the Lucy spy ring was an anti-German operation which operated in Switzerland. ... Close-up of the rotors in a Fialka cipher machine Cryptanalysis (from the Greek kryptós, hidden, and analýein, to loosen or to untie) is the study of methods for obtaining the meaning of encrypted information, without access to the secret information which is normally required to do so. ... John Cairncross (July 25, 1913 – October 8, 1995) was a British intelligence officer during World War II who, along with four other men (Kim Philby, Donald Maclean, Guy Burgess and Anthony Blunt) passed secrets to the Soviet Union during the war. ... In World War II espionage, Rudolf Roessler was the central (and mysterious) figure in the Lucy spy ring. ... Sandor (Alexander) Rado (Hungarian Radó Sándor 5 November 1899, Újpest – 1981 – Budapest) was a Hungarian-born Soviet military intelligence agent during World War II. Rado was born in a Jewish family in Újpest near Budapest. ...

Safeguarding of ULTRA sources

The Allies were seriously concerned with the prospect of the Axis command finding out that they had broken into the Enigma traffic. The British were, it is said, more disciplined about such measures than the Americans, and this difference was a source of friction between them.

Ultra information was used to attack and sink many Afrika Korps supply ships bound for North Africa; but, as in the North Atlantic, every time such information was used, an "innocent" explanation had to be provided: often scout planes were sent on otherwise unnecessary missions, to ensure they were spotted by the Germans. The seal of the Deutsches Afrikakorps. ...

In one particular case, the Germans became suspicious of Ultra when five ships from Naples headed for North Africa with essential supplies for Rommel's campaign were all mysteriously attacked and sunk by an Allied airforce. As there was no time to have the ships all spotted by the airforce beforehand and then sunk accordingly, the decision went directly to Churchill whether or not to act solely on Ultra intelligence. Churchill approved the attack, but afterwards a message was sent by the Allies to Naples congratulating a fictitious spy and informing him of his bonus. According to some sources the Germans decrypted this message and believed it.^[12]

In the Battle of Atlantic the precautions were taken to the extreme. In most cases where the Allies knew from intercepts the locations of U-boats in mid-Atlantic, the U-boats were not hunted immediately, until a "cover story" could be arranged. For example a search plane might be "fortunate enough" to sight the U-boat, thus explaining the Allied attack. U-boat is also a nickname for some diesel locomotives built by GE; see List of GE locomotives October 1939. ...

Some Germans had suspicions that all was not right with Enigma. Karl Dönitz received reports of "impossible" encounters between U-boats and enemy vessels which made him suspect some compromise of his communications. In one instance, three U-boats met at a tiny island in the Caribbean, and a British destroyer promptly showed up. They all escaped and reported what had happened. Dönitz immediately asked for a review of Enigma's security. The analysis suggested that the signals problem, if there was one, was not due to the Enigma itself. Dönitz had the settings book changed anyway, blacking out Bletchley Park for a period. However, the evidence was never enough to truly convince him that Naval Enigma was being read by the Allies. The more so, since his counterintelligence B-Dienst group, who had partially broken Royal Navy traffic (including its convoy codes early in the war),^[13] supplied enough information to support the idea that the Allies were unable to read Naval Enigma. ^[14] Karl Dönitz (IPA pronunciation:  ) (born 16 September 1891; died 24 December 1980) was a German naval leader, who commanded the German Navy (Kriegsmarine) during the second half of World War II. Dönitz was also President of Germany for 23 days after Adolf Hitlers suicide. ... West Indies redirects here. ... The B-Dienst (Beobachtungsdienst) was a German Naval codebreaking organisation During World War II, B-Dienst solved British Naval Cypher No. ...

Of course, in other cases Ultra intelligence could be taken advantage of with little or no risk of a compromise. One example was the military deception preparations for the D-day landings. These involved use of dummy tanks, fake ships and notional armies to fool the Germans into thinking that the Allied invasion would take place at the Pas de Calais, as opposed to Normandy. Ultra intelligence confirmed to the Allies that these deceptions were successful. This article is about the assault phase of Operation Overlord. ...

By 1945 almost all German Enigma traffic (Wehrmacht, Kriegsmarine, Luftwaffe, Abwehr, SD, etc.) could be decrypted within a day or two, yet the Germans remained confident of its security. Had they been better informed, they could have changed systems, forcing Allied cryptanalysts to start over.

Postwar public disclosure of Ultra

While it is obvious why Britain and the United States went to considerable pains to keep Ultra a secret until the end of the war, it has been a matter of some conjecture why Ultra was kept officially secret for 29 years thereafter, until 1974. During that period the important contributions to the war effort of a great many people remained unknown, and they were unable to share in the glory of what is likely one of the chief reasons the Allies won the war—or, at least, as quickly as they did.

At least three versions exist as to why Ultra was kept secret so long. Each has plausibility. All may be true. First, as David Kahn pointed out in his 1974 New York Times review of F.W. Winterbotham's The Ultra Secret, after World War II the British gathered up all the Enigma machines they could find and sold them to Third World countries, confident that they could continue reading the messages of the machines' new owners. A second explanation relates to a misadventure of Winston Churchill's between the World Wars, when he publicly disclosed information obtained by decrypting Russian secret communications; this had prompted the Russians to change their cryptography, leading to a cryptological blackout. The third explanation is given by Winterbotham (The Ultra Secret, introduction), who recounts that two weeks after V-E Day Churchill requested that former recipients of Ultra intelligence be asked not to divulge the source or the information they had received from it, in order that there might be neither damage to the future operations of the Secret Service nor any cause for the Allies' enemies to blame it for their defeat. David Kahn is a US historian, journalist and writer. ... Churchill redirects here. ... The German Lorenz cipher machine, used in World War II for encryption of very high-level general staff messages Cryptography (or cryptology; derived from Greek κρυπτός kryptós hidden, and the verb γράφω gráfo write or λεγειν legein to speak) is the study of message secrecy. ... Cryptology is an umbrella term for cryptography and cryptanalysis. ... Victory in Europe Day (V-E Day) was May 8, 1945, the date when the Allies during the Second World War formally celebrated the defeat of Nazi Germany and the end of Adolf Hitlers Reich. ...

Since it was British and, later, American message-breaking which had been the most extensive, this meant that the importance of Enigma decrypts to the prosecution of the war remained unknown. Discussion by either the Polish or the French of Enigma breaks carried out early in the war would have been uninformed regarding breaks carried out during the balance of the war. Nevertheless it was the public disclosure of Enigma decryption, in the book Enigma (1973) by French Intelligence officer Gustave Bertrand, that generated pressure to discuss the rest of the Enigma/Ultra story. For the song by James Blunt, see 1973 (song). ... Gustave Bertrand (died 1976) was a French military intelligence officer who made a vital contribution to the decryption, by Polands Cipher Bureau, of German Enigma ciphers beginning in December 1932. ...

The British ban was finally lifted in 1974, the year that a key participant on the distribution side of the Ultra project, F.W. Winterbotham, published The Ultra Secret. Frederick William Winterbotham (1897-1990) was a British Royal Air Force officer who during World War II was responsible for the distribution of Ultra intelligence, gleaned chiefly by decryption of German Enigma machine ciphers at Bletchley Park, fifty miles northwest of London. ...

The official history of British intelligence in World War II was published in five volumes from 1979 to 1988. It was chiefly edited by Harry Hinsley, with one volume by Michael Howard. There is also a one-volume collection of reminiscences by Ultra veterans, Codebreakers (1993), edited by Hinsley and Alan Stripp. Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... Sir Francis Harry Hinsley (26 November 1918–16 February 1998) was an English historian and cryptanalyst who worked at Bletchley Park during the Second World War and wrote widely on the history of international relations and British Intelligence during the Second World War. ...

As mentioned, after the war, surplus Enigmas and Enigma-like machines were sold to many countries around the world, which remained convinced of the security of the remarkable cipher machines. Their traffic was not so secure as they believed, however, which is of course one reason the British and Americans made the machines available. Switzerland even developed its own version of the Enigma, the NEMA, and used it for decades (at least into the late '70s). The NEMA (NEue MAschine) (new machine), also designated the T-D (Tasten-Druecker-Maschine) (key-stroke machine), was a 10-wheel rotor machine designed by the Swiss Army during World War II. Categories: Rotor machines ...

Some information about Enigma decryption did get out earlier, however. In 1967 the Polish military historian Władysław Kozaczuk in his book Bitwa o tajemnice (Battle for Secrets) first revealed that the German Enigma had been broken by Polish cryptanalysts before World War II. The same year, David Kahn in The Codebreakers described the 1945 capture of a Naval Enigma machine from U-505 and mentioned, somewhat in passing, that Enigma messages were already being read by that time, requiring "machines that filled several buildings." In 1971 Ladislas Farago's The Game of the Foxes gave an early published version of the myth of the purloined Enigma that enabled the British (according to Farago, Alfred Dillwyn Knox) to crack the cipher (Farago also mentions an Abwehr Enigma). By 1970 newer, computer-based ciphers were becoming popular as the world increasingly turned to computerised communications, and the usefulness of Enigma copies (and rotor machines generally) rapidly decreased. It was shortly after this (1974) that a decision was taken to permit some revelations about some Bletchley Park operations. WÅ‚adysÅ‚aw Kozaczuk (1923 — 2003, Warsaw, Poland) was a Polish historian who published a dozen books, several of them in multiple editions. ... The Codebreakers - The Story of Secret Writing (ISBN 0684831309) is a book written by David Kahn in 1967 chronicling the history of cryptology from ancient Egypt to the time of its writing. ... Ladislas Farago was a journalist who published a number of popular books on history and espionage, especially concerning the World War II era. ... Alfred Dillwyn Dilly Knox (1884–27 February 1943) was a British codebreaker and Greek scholar at Kings College, Cambridge. ... The Abwehr was a German intelligence organization from 1921 to 1944. ...

The United States National Security Agency retired the last of its rotor-based encryption systems, the KL-7 series, in the 1980s. NSA redirects here. ... KL-7 on display at USAF Communications Agency museum. ...

Ultra's tactical & strategic consequences

There has been controversy about the influence of Allied Enigma decryption on the course of World War II. Probably the question should be broadened to include Ultra's influence not only on the war itself, but on the postwar period as well.

Wartime consequences

Wintebotham summarizes the wartime consequences in the last chapter of his book. ^[5]

In May 1940 the Allies failed to take advantage of Ultra in France, especially the French, although Ultra intelligence helped organize evacuation of the British Expeditionary Force (BEF).

In the summer of 1940, British cryptanalysts, who were successfully breaking German Air Force Enigma-cypher variants, were able to give Churchill information about the issuing of maps of England and Ireland to the Sealion invasion forces. Ultra also revealed to the British that the threat of invasion was over, when on September 17 Hitler authorized the dismantling of aircraft loading ramps at Dutch airfields. Operation Sealion (Unternehmen Seelöwe in German) was a World War II German plan to invade Britain. ... is the 260th day of the year (261st in leap years) in the Gregorian calendar. ...

During the Battle of Britain, Ultra intelligence was used by Air Chief Marshal Sir Hugh Dowding to optimally deploy the limited RAF Fighter Command assets. This article is about the Second World War battle. ... “Dowding” redirects here. ... Fighter Command was one of three functional commands that dominated the public perception of the RAF for much of the mid-20th century. ...

Breaking of some messages (not in German Enigma) led to the defeat of the Italian Navy at Cape Matapan, and was preceded by another "fortuitous" search-plane sighting. British Admiral Cunningham also did some fancy footwork at a hotel in Egypt to prevent Axis agents from taking note of his movements and deducing that a major operation was planned. Combatants United Kingdom Australia Italy Commanders Andrew Cunningham Angelo Iachino Strength 1 aircraft carrier 3 battleships 7 light cruisers 17 destroyers 1 battleship 6 heavy cruisers 2 light cruisers 17 destroyers Casualties 4 light cruiser lightly damaged 1 torpedo bomber destroyed 3 dead 1 battleship heavily damaged 3 heavy cruisers... Admiral of the Fleet Sir Andrew Cunningham Bronze bust of Lord Cunningham, looking at Nelsons column and Whitehall Sir Andrew Browne Cunningham, 1st Viscount Cunningham of Hyndhope (7 January 1883–12 June 1963), familiarly known as ABC, was a famous British admiral of World War II, winning distinction in...

Ultra intelligence was of considerable assistance to the British (Montgomery being "in the know" about Ultra) at El Alamein in Western Egypt in the long-running battle with the Afrika Korps under Rommel. Bernard Law Montgomery Field Marshal Bernard Law Montgomery, 1st Viscount Montgomery of Alamein (November 17, 1887 - March 24, 1976) was a British military officer during World War II often referred to as Monty. ... Rommel is the family name of Eddie Rommel baseball pitcher; Erwin Rommel (German Field Marshal), and his son Manfred Rommel (former Mayor of Stuttgart). ...

Intelligence from signals between Adolf Hitler and General Günther von Kluge was of considerable help during the campaign in France just after the Allied D-Day landings, particularly in regard to estimates of when German reserves might be committed to battle. Günther “Hans” von Kluge (October 30, 1882 – August 19, 1944), was a German military leader. ...

On the other hand, the Red Army was well aware of the German buildup, locations and attack time precisely, prior to the battle of Kursk even without the Ultra information provided to them.^{[citation needed]} However, there is some evidence to suggest that the Lucy spy ring of Switzerland, which provided crucial information about Stalingrad and Kursk, was in truth a method of passing Ultra information to Moscow without detection by the Germans. Belligerents Nazi Germany Soviet Union Commanders Erich von Manstein Günther von Kluge Hermann Hoth Walther Model Hans Seidemann Robert Ritter von Greim Georgiy Zhukov Konstantin Rokossovskiy Nikolay Vatutin Ivan Konyev Strength 2,700 tanks 800,000 infantry 2,109 aircraft[1] 3,600 tanks 20,000 guns[2] 1...

Battle of the Atlantic

It is commonly claimed that the breaks into Naval Enigma resulted in the war being a year shorter, but given its effects on the Second Battle of the Atlantic alone, that might be an underestimate. Combatants Royal Navy Royal Canadian Navy United States Navy Kriegsmarine Regia Marina Commanders Sir Percy Noble Sir Max K. Horton Ernest J. King Erich Raeder Karl Dönitz Casualties 30,248 merchant sailors 3,500 merchant vessels 175 warships 28,000 sailors 783 submarines The Second Battle of the Atlantic...

An exhibit in 2003 on "Secret War" at the Imperial War Museum, in London, quoted British Prime Minister Winston Churchill telling King George VI, "It was thanks to Ultra that we won the war." Churchill's greatest fear, even after Hitler had suspended Operation Sealion and invaded the Soviet Union, was that the German submarine wolf packs would succeed in strangling sea-locked Britain. He would later write, in Their Finest Hour (1949), "The only thing that ever really frightened me during the war was the U-boat peril." A major factor that averted Britain's defeat in the Battle of the Atlantic was her regained mastery of Naval Enigma decryption. The Imperial War Museum is a museum in London featuring military vehicles, weapons, war memorabilia, a library, a photographic archive, and an art collection of 20th century and later conflicts, especially those involving Britain, and the British Empire. ... Churchill redirects here. ... Operation Sealion (Unternehmen (Undertaking) Seelöwe in German) was a World War II German plan to invade the United Kingdom. ... For other uses, see Submarine (disambiguation). ... The term wolf pack refers to the mass-attack tactics against convoys used by U-boats of the Kriegsmarine during the Battle of the Atlantic and submarines of the United States Navy against Japanese shipping in the Pacific Ocean in World War II. Karl Dönitz used the term Rudel... Combatants Royal Navy Royal Canadian Navy United States Navy Kriegsmarine Regia Marina Commanders Sir Percy Noble Sir Max K. Horton Ernest J. King Erich Raeder Karl Dönitz Casualties 30,248 merchant sailors 3,500 merchant vessels 175 warships 28,000 sailors 783 submarines The Second Battle of the Atlantic... This article or section contains information that has not been verified and thus might not be reliable. ...

There were, however, also other technologies, equipments, and tactics which moved the Battle of the Atlantic in the Allies' favour. As the air gap over the North Atlantic closed and convoys received escort carrier protection, anti-submarine aircraft became extremely efficient hunter-killers with the use of centimetric radar and airborne depth charges. Improvements to Huff-Duff (radio triangulation equipment used as part of ELINT) meant a U-boat's location could be found even if the messages they were sending could not be read (and simply avoiding a known submarine was often sufficient). Improvements to ASDIC (SONAR), coupled with Hedgehog, improved the likelihood of sinking a U-boat. The escort aircraft carrier or escort carrier, was a small aircraft carrier developed by the Royal Navy in the early part of World War II to deal with the U-boat crisis of the Battle of the Atlantic. ... The history of radar began in the 1900s when engineers invented reflection devices. ... Depth Charge used by U.S. Navy later in World War II The depth charge is the oldest anti-submarine weapon. ... High Frequency Direction Finder is usually known by its acronym HF/DF, pronounced Huff-Duff. ... ELINT stands for ELectronic INTelligence, and refers to intelligence-gathering by use of electronic sensors. ... This article is about underwater sound propagation. ... Hedgehog anti-submarine weapon, British WWII Hedgehog anti-submarine mortar with full load of practice bombs, circa 2002. ...

Bombing of German cities

From February 1942, when Air Marshal Arthur Harris became Air Officer Commanding of Bomber Command, the RAF implemented large-scale night area bombardment of German cities. The destruction of city centres not only killed civilians and destroyed factories, houses and railways, but damaged and degraded the telephone and telex network. Usually the long-distance cable network was rapidly repaired, so that the still running telex network was closed down by Allied order only on 8th May, 1945. However, a surge in communications demand by German command and control and the effect of unrepaired destructions forced the Germans, as the war progressed, to rely ever more heavily on encrypted radio traffic, which of course the Allies were able to read. An air marshals sleeve/shoulder insignia Air Marshal (Air Mshl or AM) is a rank in the Royal Air Force. ... Sir Arthur Travers Harris, 1st Baronet (April 13, 1892 - April 5, 1984), commonly known as Bomber Harris, and often, in the RAF, as Butcher Harris, was commander of RAF Bomber Command and later a Marshal of the Royal Air Force during the latter half of World War II. In 1942... Commander-in-Chief (in NATO-lingo often C-in-C or CINC pronounced sink) is the commander of all the military forces within a particular region or of all the military forces of a state. ... Bomber Command badge RAF Bomber Command was the organisation that controlled the RAFs bomber forces. ... Area bombardment is the policy of indiscriminate bombing of an enemys cities, for the purpose of destroying civilian morale. ...

After D-Day, with the resumption of the strategic bomber campaign over Germany, Harris remained wedded to area bombardment. Historian Frederick Taylor argues, as Harris was not cleared for access to ULTRA, he was given some information gleaned from Enigma but not the information's source. This affected his attitude about post-D-Day directives (orders) to target oil installations, since he did not know senior Allied commanders were using high-level German sources to assess just how much this was hurting the German war effort, so Harris tended to see the directives to bomb specific oil and munitions targets as a "panacea" (his word), and a distraction from the real task of making the rubble bounce in every large German city.^[15] Frederick Taylor is a British historian, author of , Bloomsbury 2004 (ISBN 0747570787) about the bombing of Dresden in World War II. He was educated at Aylesbury Grammar School and read History and Modern Languages at Oxford University. ...

Postwar consequences

F.W. Winterbotham, the first author to outline, in his 1974 book The Ultra Secret, the influence of Enigma decryption on the course of World War II, likewise made the earliest contribution to an appreciation of Ultra's postwar influence, which now continues into the 21st century—and not only in the postwar establishment of Britain's GCHQ (Government Communication Headquarters) and the United States' NSA (National Security Agency). "Let no one be fooled," Winterbotham admonishes in chapter 3, "by the spate of television films and propaganda which has made the war seem like some great triumphant epic. It was, in fact, a very narrow shave, and the reader may like to ponder [...] whether [...] we might have won [without] Ultra." Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... The Government Communications Headquarters (GCHQ) (previously named the Government Code and Cipher School (GC&CS)) is the main British intelligence service providing signals intelligence (SIGINT). ... NSA can stand for: National Security Agency of the USA The British Librarys National Sound Archive This page concerning a three-letter acronym or abbreviation is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ...

See also

• Military intelligence
• Hut 6
• Hut 8
• Magic (cryptography)

Military intelligence (abbreviated MI, int. ... Hut 6 at Bletchley Park in 2004 Hut 6 was a wartime section of Bletchley Park tasked with the solution of German Army and Air Force Enigma machine ciphers. ... Hut 8 was one of the units at Bletchley Park, the secret British military intelligence operation that opened just before World War II. Led by Alan Turing, Hut 8 was assigned to break the German naval Enigma code. ... In World War II, Magic was the United States codename for intelligence derived from the cryptanalysis of PURPLE, a Japanese foreign office cipher. ...

Notes and References

The name MI8 was temporarily applied to a cryptography effort mounted within the US Army during World War I. Herbert Yardley was assigned to this unit during the War, and after it continued his cryptographic work during the 1920s at what Yardley called the American Black Chamber in his book... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Common Era (or Anno Domini), in accordance with the Gregorian calendar. ... is the 49th day of the year in the Gregorian calendar. ...

Further reading

• Winterbotham, F.W. (2000 [1974]). The ULTRA Secret. Orion Books Ltd. ISBN 0-75283-751-6. 

• United Kingdom WWII Ultra. Retrieved on 2008-02-15. Extensive literature list on ULTRA.

• The story is also somewhat covered, fictionally, in Neal Stephenson's Cryptonomicon (ISBN 0-09-941067-2).

• A short account of World War II cryptology is Stephen Budiansky's Battle of Wits (2000). It covers more than just the Enigma story.

• Hugh Sebag-Montefiore (2000). Enigma: the Battle for the Code. Cassel Military Paperbacks. ISBN 0-304-36662-5.  This book focuses largely on Naval Enigma, includes some previously unknown information—and many photographs of individuals involved. Bletchley Park had been his grandfather's house before it was purchased for GC&CS.

• David Kahn's Seizing the Enigma (1991) is essentially about the solution of Naval Enigma, based on seizures of German naval vessels. British success in the endeavor almost certainly saved Britain from defeat in the crucial Battle of the Atlantic and thereby made the United States' entry into the war's European theater possible.

• Thomas Parrish. The American Codebreakers.  This book, earlier published as The Ultra Americans, concentrates on the U.S. contribution to the codebreaking effort.

• Welchman, G. (1997). The Hut Six Story. M&M Baldwin, 158. ISBN 0-947712-34-8.  Describes briefly production of intelligence in BP Hut 3.

• A description of the Enigma, as well as other codes/ciphers, can be found in Simon Singh's The Code Book (1999).

• Information on British cryptology appears in the official history of British intelligence in World War II, edited by Sir Harry Hinsley. He also co-edited, with Alan Stripp, a volume of memoirs by participants in the British cryptological effort, Codebreakers: the Inside Story of Bletchley Park (1993).

• Marian Rejewski wrote a number of papers on his 1932 break into Enigma and his subsequent work on the cipher, well into World War II, with his fellow mathematician-cryptologists, Jerzy Różycki and Henryk Zygalski. Most of Rejewski's papers appear in Władysław Kozaczuk's 1984 Enigma: How the German Machine Cipher Was Broken, and How It Was Read by the Allies in World War Two (edited and translated by Christopher Kasparek), which remains the standard reference on the crucial foundations laid by the Poles for World War II Enigma decryption.

• Broken Enigma messages are still extremely valuable today, as they provide some of the best surviving direct accounts of the Nazi war effort.

• Ronald Lewin (1978). Ultra goes to War. 

• John Winton (1988). Ultra at Sea. 

• Nigel West (1986). The SIGINT Secrets The Signals Intelligence War 1900 to Today. 

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