ULTRA

ULTRA was a code word for British communications intelligence (COMINT) in the Second World War, primarily targeted against the German Enigma machine and its derivatives. . This was one of the greatest intelligence triumphs in the history of warfare; the British read many German messages throughout the war.

The COMINT organization was called the Government Code and Cipher School (GCCS), which reported to the Secret Intelligence Service. Eventually, GCCS became a separate organization, the Government Communications Headquarters, with functions similar to the Canadian Communications Security Establishment or the U.S. National Security Agency.

Before the war

The Enigma was first built in the 1920s and was adopted by the German military in the late 20s. The first break was achieved in 1931 by Polish Intelligence. A bit later, Marian Rejewski broke the more complex version with a plugboard. The Poles had a novel approach; previously, cryptanalysis had been largely done by linguists, but solving machine ciphers needed sophisticated mathematical techniques. It also used machines; the Poles produced the first "bomba", a machine for quickly finding enigma keys, in 1938.

The Poles continued to read Enigma throughout the 30s, improving their techniques as they went along, but they naturally kept their secret, even from their allies. However in 1939, with war looming, they revealed the Enigma attacks to Britain and France. When the war actually started, key people and equipment were evacuated to Romania and thence to France.

Bletchley Park and the early days

Alan Turing, a Cambridge mathematician known at Bletchley as "prof" was one of the key figures. He had done extensive work before the war or the formal theory of computation, including inventing the Turing Machine. At Bletchley, he was a contributor to Bombe and Collosus design and the main player in breaking the U-boats' four-rotor enigma.

Bletchley Park now has a museum and a web site [1]. In 2008, they ran low on money and an appeal was made [2] for funds to keep it going. Respondents include several major hi-tech companies [3].

Fictional treatments

Neal Stephenson's novel Cryptonomicon [4] has a great deal of cryptography in it. Parts of it take place around the turn of the 21st century, but other parts follow the grandparents of the 21st-century characters through the Second World War. Lawrence Waterhouse is an American who meets Turing at Princeton, learns cryptanalysis from a character apparently base on Friedman, and later works at Bletchley. Bobby Shaftoe is a Marine Sergeant who does a lot of rather strange missions at Bletchley and Waterhouse's behest.

The 2001 film Enigma [5], directed by Michael Apted, takes place largely at Bletchley. There is a character clearly based on Turing, a Cambridge mathematician who has solved a major German naval cipher, but in the film he is not gay; much of the plot centers on his relationship with a lovely young woman.