Ultra (cryptography)
"[9] However, Hinsley and others have emphasized the difficulties of counterfactual history in attempting such conclusions, and some historians, such as Keegan, have said the shortening might have been as little as the three months it took the United States to deploy the atomic bomb.
For example, Andrew Roberts, writing in the 21st century, states, "Because he had the invaluable advantage of being able to read Field Marshal Erwin Rommel's Enigma communications, General Bernard Montgomery knew how short the Germans were of men, ammunition, food and above all fuel.
[21] Gordon Welchman wrote, 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.At Bletchley Park, some of the key people responsible for success against Enigma included mathematicians Alan Turing and Hugh Alexander and, at the British Tabulating Machine Company, chief engineer Harold Keen.
[23] The Poles' early start at breaking Enigma and the continuity of their success gave the Allies an advantage when World War II began.
[22] 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.
[16] At Bletchley Park, some of the key people responsible for success in the Tunny effort included mathematicians W. T. "Bill" Tutte and Max Newman and electrical engineer Tommy Flowers.
Mobile SLUs were attached to field army and air force headquarters and depended on radio communications to receive intelligence summaries.
[36] The communications system was founded by Brigadier Sir Richard Gambier-Parry, who from 1938 to 1946 was head of MI6 Section VIII, based at Whaddon Hall in Buckinghamshire, UK.
RN Ultra messages from the OIC to ships at sea were necessarily transmitted over normal naval radio circuits and were protected by one-time pad encryption.
[38] An intriguing question concerns the alleged use of Ultra information by the "Lucy" spy ring,[39] headquartered in Switzerland and apparently operated by one man, Rudolf Roessler.
It has been alleged that "Lucy" was in major part a conduit for the British to feed Ultra intelligence to the Soviets in a way that made it appear to have come from highly placed espionage rather than from cryptanalysis of German radio traffic.
[43] The indices included message preambles, every person, every ship, every unit, every weapon, every technical term and of repeated phrases such as forms of address and other German military jargon that might be usable as cribs.
[44] The first decryption of a wartime Enigma message, albeit one that had been transmitted three months earlier, was achieved by the Poles at PC Bruno on 17 January 1940.
Rommel was appointed Inspector General of the West, and he inspected all the defences along the Normandy beaches and send a very detailed message that I think was 70,000 characters and we decrypted it as a small pamphlet.
To distract the Germans from the idea of a signals breach (such as Ultra), the Allies sent a radio message to a fictitious spy in Naples, congratulating him for this success.
The more so, since B-Dienst, his own codebreaking group, had partially broken Royal Navy traffic (including its convoy codes early in the war),[84] and supplied enough information to support the idea that the Allies were unable to read Naval Enigma.
[91] It allows a contemporary, documentary view of a leader on Ultra's importance: July 1945 Dear General Menzies: I had hoped to be able to pay a visit to Bletchley Park in order to thank you, Sir Edward Travis, and the members of the staff personally for the magnificent service which has been rendered to the Allied cause.
The graphs cannot be interpreted unambiguously, because it is challenging to factor in many variables such as improvements in cipher-breaking and the numerous other advances in equipment and techniques used to combat U-boats.
"[11] Military historian Guy Hartcup analyzes aspects of the question but then simply says, "It is impossible to calculate in terms of months or years how much Ultra shortened the war.
[95][better source needed] By the 1970s, 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.
Switzerland developed its own version of Enigma, known as NEMA, and used it into the late 1970s, while the United States National Security Agency (NSA) retired the last of its rotor-based encryption systems, the KL-7 series, in the 1980s.
For they had, more than a year before the theft, succeeded in solving the difficult U-boat systems, and – in one of the finest cryptanalytic achievements of the war – managed to read the intercepts on a current basis.
"[99] "In 1941 [t]he brilliant cryptologist Dillwyn Knox, working at the Government Code & Cypher School at the Bletchley centre of British code-cracking, solved the keying of the Abwehr's Enigma machine.
A 2012 London Science Museum exhibit, "Code Breaker: Alan Turing's Life and Legacy",[102] marking the centenary of his birth, includes a short film of statements by half a dozen participants and historians of the World War II Bletchley Park Ultra operations.
He further states that it is only in 2012 that Alan Turing's last two papers on Enigma decryption have been released to Britain's National Archives; the seven decades' delay had been due to their "continuing sensitivity...
Historians and Holocaust researchers have tried to establish when the Allies realized the full extent of Nazi-era extermination of Jews, and specifically, the extermination-camp system.
"[104] Following Operation Barbarossa, decrypts in August 1941 alerted British authorities to the many massacres in occupied zones of the Soviet Union, including those of Jews, but specifics were not made public for security reasons.
[105] Revelations about the concentration camps were gleaned from other sources, and were publicly reported by the Polish government-in-exile, Jan Karski and the WJC offices in Switzerland a year or more later.
The Soviets, who had clues to Ultra's existence, possibly through Kim Philby, John Cairncross and Anthony Blunt,[110] may thus have felt still more distrustful of their wartime partners.
The mystery surrounding the discovery of the sunk German submarine U-869 off the coast of New Jersey by divers Richie Kohler and John Chatterton was unravelled in part through the analysis of Ultra intercepts, which demonstrated that, although U-869 had been ordered by U-boat Command to change course and proceed to North Africa, near Rabat, the submarine had missed the messages changing her assignment and had continued to the eastern coast of the U.S., her original destination.
