Peter Twinn
Encyclopedia
Peter Frank George Twinn (9 January 1916 – 29 October 2004) was a British mathematician
, World War II
codebreaker
and entomologist.
, South London
, Twinn was the son of a senior General Post Office
official. After attending Manchester Grammar School
and Dulwich College
, he graduated in mathematics
at Brasenose College, Oxford
. He won a scholarship to pursue postgraduate studies in Physics
.
Twinn joined GC&CS—Britain's codebreaking service—in early 1939, recruited after seeing an advertisement, working first in London before moving to Bletchley Park
. He worked with Dilly Knox
and Alan Turing
on German Enigma ciphers. In early 1942, he became the head of the Abwehr Enigma section.
Twinn was the first British cryptographer to read a German military Enigma message, having obtained vital information from Polish cryptanalysts in July 1939. Twinn stated that, "It was a trifling exercise, but I repeat for the umpteenth time, no credit to me."
In that unsettled period after the Munich Agreement, international relations between the major European powers were tense and getting tenser.
" They offered me this job at the princely salary of, I think, £275 a year," he said, "which sounded all right to me, and I was taken along on the first day to be introduced to Dilly Knox." He began as an assistant to Alfred Dilwyn (“Dilly”) Knox, who headed a team of codebreakers at GC&CS.
An eccentric but brilliant character, Dilly Knox was the first British codebreaker to work on the Enigma cipher. Like most GC&CS experts, he was a classicist. But, as war loomed, GC&CS began employing mathematicians, as well as chess players and crossword experts. Twinn was in fact the first mathematician to join the team.
Knox believed in throwing his new recruits in at the deep end. He gave Twinn a mere five minutes’ training before telling him to go and get on with it.
The Enigma machine dated back to 1919, when Hugo Alexander Koch, a Dutchman, patented an invention that he called a secret writing machine. A little later, Arthur Scherbius, an engineer, was experimenting with this and similar machines and became enthusiastic about encryption machines that used rotors. He recommended them to Siegfried Turkel, the director of the Institute of Criminology in Vienna, who also became interested in them.
In the meantime, Koch had set up a company with the hope of selling his encryption machine for commercial use. But industry was not interested. However, in 1926 the German Navy looked at the Koch machine. Senior officers were impressed with it and ordered a large number. The purchase of the device — called Enigma — was kept strictly secret.
The Enigma machine was a very complicated instrument. It had a keyboard, like the ones used on a typewriter, containing all the letters of the alphabet. Each of the 26 letters was connected electrically to one of three rotors, each provided with a ring. Each ring also held the 26 letters of the alphabet. Further electrical connections led from the rotors to 26 illuminated letters.
When an operator, enciphering a message, pressed a key, an electric current passed through the machine and the rotors turned mechanically, but not in unison. Every time a key was pushed, the first rotor would rotate one letter. This happened 26 times until the first rotor had made a complete revolution. Then the second rotor would start to rotate. And so on.
When a key was pressed, a light came on behind the cipher text letter, always different from the original letter in the plain text. The illuminated letters made up the coded message.
The system worked in reverse. The person decoding a cipher message would use an Enigma with identical settings. When he pressed the cipher text letter, the letter in the original plain text message lit up. The illuminated letters made up the original message.
To make the codes more difficult to break, each of the rotors could be taken out and replaced in a different order. Also, the rings on the rotors could be put in a different order each day — for example, on one day the first rotor could be set at B, the next day at F, and so on.
The military version of Enigma was provided with a plug board, like an old telephone switchboard. This allowed an extra switching of the letters, both before they entered the rotors and after leaving them. The plug board had 26 holes. Connections were made with wires and plugs. With three rotors and, say, six pairs of letters connected with the plug board, there would be 105,456 different combinations of the alphabet.
In December 1938 the Germans added additional rotors (up to six) and the number of combinations increased dramatically. The Germans believed that messages sent on their most sophisticated Enigma machines were so well coded that they could not be decoded. But Twinn and his colleagues proved them wrong.
In July 1939 GC&CS moved from London to Bletchley Park. The mansion in the park was used by the staff, but many other buildings had to be constructed to accommodate the large number of people who worked for GC&CS during the war. These temporary buildings were known as the “huts”.
About 10,000 people worked at Bletchley. The core group was the small number of cryptanalysts trying to crack the Enigma machine; at the beginning, this group consisted of no more than ten people, with Knox and Twinn in charge.
The British codebreakers had been working on the commercial version of Enigma, the easier of the two to break, during the 1920s and 1930s, and they had made much progress in breaking the military version. But Twinn and his colleagues were stymied because they could not work out the order in which the Enigma keys were wired up.
In July 1939, a month or so before the war started, Knox and some others travelled to Poland. Polish cryptologists, some of whom were brilliant, handed over to their British colleagues key information about Enigma, including replica machines.
The British discovered that Enigma machines were wired alphabetically: A to the first contact, B to the second, and so on. This was the order given in the diagram attached to the patent application. But Twinn and his colleagues thought it such an obvious thing to do that nobody considered it worth trying.
In early 1940 Twinn made the first break into Enigma. This could have been done much earlier if only they had tried the alphabetical system detailed in the patent application.
The ability to read German encoded military messages was of inestimable help to the Allies in winning the war. It was achieved largely because of the efforts of Twinn, Knox, Alan Turing (who later became the father of artificial intelligence) and others at Bletchley Park. Turing, a brilliant mathematician, developed a machine called the “bombe”, which speeded up the deciphering process by trial and error — a crucial development for the codebreakers.
Twinn worked with Turing on breaking the German Naval Enigma. Their success helped allied convoys to avoid German U-boats. Knox worked on the German Army (Abwehr) codes, a task that Twinn took over when Knox became ill. This operation was crucial in the Allied campaign to deceive the Germans about their plans to invade Normandy in June 1944. The work of GC&CS, however, remained one of Britain’s best-kept secrets until 1974, nearly 30 years after the end of the war.
in the Ministry for Technology. Later he became Secretary of the Royal Aircraft Establishment
in Farnborough
. In the early 1970s, he was the second secretary of the Natural Environment Research Council
.
Twinn became interested in entomology
, gaining his doctorate from the University of London
in the jumping mechanism of click beetle
s. He co-authored A Provisional Atlas of the Longhorn Beetle (Coleoptera Cerambycidae) (1999), a study of the distribution of a number of beetle species.
Twinn had an interest in music and played the clarinet
and viola
. Twinn married Rosamund Case, whom he had met at Bletchley Park
through his interest in music, in 1944; they had a son and three daughters.
Mathematician
A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....
, World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
codebreaker
Codebreaker
Codebreaker may refer to:*A person who performs cryptanalysis*The Codebreakers, a 1967 book on history of cryptography by David Kahn*Codebreaker , a 1981 puzzle-based computer game, originally released for the Atari 2600...
and entomologist.
Education and codebreaking
Born in StreathamStreatham
Streatham is a district in Surrey, England, located in the London Borough of Lambeth. It is situated south of Charing Cross. The area is identified in the London Plan as one of 35 major centres in Greater London.-History:...
, South London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
, Twinn was the son of a senior General Post Office
Post office
A post office is a facility forming part of a postal system for the posting, receipt, sorting, handling, transmission or delivery of mail.Post offices offer mail-related services such as post office boxes, postage and packaging supplies...
official. After attending Manchester Grammar School
Manchester Grammar School
The Manchester Grammar School is the largest independent day school for boys in the UK . It is based in Manchester, England...
and Dulwich College
Dulwich College
Dulwich College is an independent school for boys in Dulwich, southeast London, England. The college was founded in 1619 by Edward Alleyn, a successful Elizabethan actor, with the original purpose of educating 12 poor scholars as the foundation of "God's Gift". It currently has about 1,600 boys,...
, he graduated in mathematics
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...
at Brasenose College, Oxford
Brasenose College, Oxford
Brasenose College, originally Brazen Nose College , is one of the constituent colleges of the University of Oxford in the United Kingdom. As of 2006, it has an estimated financial endowment of £98m...
. He won a scholarship to pursue postgraduate studies in Physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
.
Twinn joined GC&CS—Britain's codebreaking service—in early 1939, recruited after seeing an advertisement, working first in London before moving to Bletchley Park
Bletchley Park
Bletchley Park is an estate located in the town of Bletchley, in Buckinghamshire, England, which currently houses the National Museum of Computing...
. He worked with Dilly Knox
Dilly Knox
Alfred Dillwyn 'Dilly' Knox CMG was a classics scholar at King's College, Cambridge, and a British codebreaker...
and Alan Turing
Alan Turing
Alan Mathison Turing, OBE, FRS , was an English mathematician, logician, cryptanalyst, and computer scientist. He was highly influential in the development of computer science, providing a formalisation of the concepts of "algorithm" and "computation" with the Turing machine, which played a...
on German Enigma ciphers. In early 1942, he became the head of the Abwehr Enigma section.
Twinn was the first British cryptographer to read a German military Enigma message, having obtained vital information from Polish cryptanalysts in July 1939. Twinn stated that, "It was a trifling exercise, but I repeat for the umpteenth time, no credit to me."
The World War II Story
He was in the middle of a postgraduate scholarship studying Physics when he saw an advertisement for a job with the government. "I was a bit unsettled," he remembered. "I'd finished my university degree and I didn't quite know what to do." The advertisement indicated that they were looking for mathematicians, but was unclear about what else was involved.In that unsettled period after the Munich Agreement, international relations between the major European powers were tense and getting tenser.
" They offered me this job at the princely salary of, I think, £275 a year," he said, "which sounded all right to me, and I was taken along on the first day to be introduced to Dilly Knox." He began as an assistant to Alfred Dilwyn (“Dilly”) Knox, who headed a team of codebreakers at GC&CS.
An eccentric but brilliant character, Dilly Knox was the first British codebreaker to work on the Enigma cipher. Like most GC&CS experts, he was a classicist. But, as war loomed, GC&CS began employing mathematicians, as well as chess players and crossword experts. Twinn was in fact the first mathematician to join the team.
Knox believed in throwing his new recruits in at the deep end. He gave Twinn a mere five minutes’ training before telling him to go and get on with it.
The Enigma machine dated back to 1919, when Hugo Alexander Koch, a Dutchman, patented an invention that he called a secret writing machine. A little later, Arthur Scherbius, an engineer, was experimenting with this and similar machines and became enthusiastic about encryption machines that used rotors. He recommended them to Siegfried Turkel, the director of the Institute of Criminology in Vienna, who also became interested in them.
In the meantime, Koch had set up a company with the hope of selling his encryption machine for commercial use. But industry was not interested. However, in 1926 the German Navy looked at the Koch machine. Senior officers were impressed with it and ordered a large number. The purchase of the device — called Enigma — was kept strictly secret.
The Enigma machine was a very complicated instrument. It had a keyboard, like the ones used on a typewriter, containing all the letters of the alphabet. Each of the 26 letters was connected electrically to one of three rotors, each provided with a ring. Each ring also held the 26 letters of the alphabet. Further electrical connections led from the rotors to 26 illuminated letters.
When an operator, enciphering a message, pressed a key, an electric current passed through the machine and the rotors turned mechanically, but not in unison. Every time a key was pushed, the first rotor would rotate one letter. This happened 26 times until the first rotor had made a complete revolution. Then the second rotor would start to rotate. And so on.
When a key was pressed, a light came on behind the cipher text letter, always different from the original letter in the plain text. The illuminated letters made up the coded message.
The system worked in reverse. The person decoding a cipher message would use an Enigma with identical settings. When he pressed the cipher text letter, the letter in the original plain text message lit up. The illuminated letters made up the original message.
To make the codes more difficult to break, each of the rotors could be taken out and replaced in a different order. Also, the rings on the rotors could be put in a different order each day — for example, on one day the first rotor could be set at B, the next day at F, and so on.
The military version of Enigma was provided with a plug board, like an old telephone switchboard. This allowed an extra switching of the letters, both before they entered the rotors and after leaving them. The plug board had 26 holes. Connections were made with wires and plugs. With three rotors and, say, six pairs of letters connected with the plug board, there would be 105,456 different combinations of the alphabet.
In December 1938 the Germans added additional rotors (up to six) and the number of combinations increased dramatically. The Germans believed that messages sent on their most sophisticated Enigma machines were so well coded that they could not be decoded. But Twinn and his colleagues proved them wrong.
In July 1939 GC&CS moved from London to Bletchley Park. The mansion in the park was used by the staff, but many other buildings had to be constructed to accommodate the large number of people who worked for GC&CS during the war. These temporary buildings were known as the “huts”.
About 10,000 people worked at Bletchley. The core group was the small number of cryptanalysts trying to crack the Enigma machine; at the beginning, this group consisted of no more than ten people, with Knox and Twinn in charge.
The British codebreakers had been working on the commercial version of Enigma, the easier of the two to break, during the 1920s and 1930s, and they had made much progress in breaking the military version. But Twinn and his colleagues were stymied because they could not work out the order in which the Enigma keys were wired up.
In July 1939, a month or so before the war started, Knox and some others travelled to Poland. Polish cryptologists, some of whom were brilliant, handed over to their British colleagues key information about Enigma, including replica machines.
The British discovered that Enigma machines were wired alphabetically: A to the first contact, B to the second, and so on. This was the order given in the diagram attached to the patent application. But Twinn and his colleagues thought it such an obvious thing to do that nobody considered it worth trying.
In early 1940 Twinn made the first break into Enigma. This could have been done much earlier if only they had tried the alphabetical system detailed in the patent application.
The ability to read German encoded military messages was of inestimable help to the Allies in winning the war. It was achieved largely because of the efforts of Twinn, Knox, Alan Turing (who later became the father of artificial intelligence) and others at Bletchley Park. Turing, a brilliant mathematician, developed a machine called the “bombe”, which speeded up the deciphering process by trial and error — a crucial development for the codebreakers.
Twinn worked with Turing on breaking the German Naval Enigma. Their success helped allied convoys to avoid German U-boats. Knox worked on the German Army (Abwehr) codes, a task that Twinn took over when Knox became ill. This operation was crucial in the Allied campaign to deceive the Germans about their plans to invade Normandy in June 1944. The work of GC&CS, however, remained one of Britain’s best-kept secrets until 1974, nearly 30 years after the end of the war.
Post-war career
Twinn's carried on government work after the war in a number of departments, including, in the late 1960s, as Director of HovercraftHovercraft
A hovercraft is a craft capable of traveling over surfaces while supported by a cushion of slow moving, high-pressure air which is ejected against the surface below and contained within a "skirt." Although supported by air, a hovercraft is not considered an aircraft.Hovercraft are used throughout...
in the Ministry for Technology. Later he became Secretary of the Royal Aircraft Establishment
Royal Aircraft Establishment
The Royal Aircraft Establishment , was a British research establishment, known by several different names during its history, that eventually came under the aegis of the UK Ministry of Defence , before finally losing its identity in mergers with other institutions.The first site was at Farnborough...
in Farnborough
Farnborough, Hampshire
-History:Name changes: Ferneberga ; Farnburghe, Farenberg ; Farnborowe, Fremborough, Fameborough .Tower Hill, Cove: There is substantial evidence...
. In the early 1970s, he was the second secretary of the Natural Environment Research Council
Natural Environment Research Council
The Natural Environment Research Council is a British research council that supports research, training and knowledge transfer activities in the environmental sciences.-History:...
.
Twinn became interested in entomology
Entomology
Entomology is the scientific study of insects, a branch of arthropodology...
, gaining his doctorate from the University of London
University of London
-20th century:Shortly after 6 Burlington Gardens was vacated, the University went through a period of rapid expansion. Bedford College, Royal Holloway and the London School of Economics all joined in 1900, Regent's Park College, which had affiliated in 1841 became an official divinity school of the...
in the jumping mechanism of click beetle
Click beetle
The family Elateridae is commonly called click beetles , elaters, snapping beetles, spring beetles or "skipjacks". They are a cosmopolitan beetle family characterized by the unusual click mechanism they possess...
s. He co-authored A Provisional Atlas of the Longhorn Beetle (Coleoptera Cerambycidae) (1999), a study of the distribution of a number of beetle species.
Twinn had an interest in music and played the clarinet
Clarinet
The clarinet is a musical instrument of woodwind type. The name derives from adding the suffix -et to the Italian word clarino , as the first clarinets had a strident tone similar to that of a trumpet. The instrument has an approximately cylindrical bore, and uses a single reed...
and viola
Viola
The viola is a bowed string instrument. It is the middle voice of the violin family, between the violin and the cello.- Form :The viola is similar in material and construction to the violin. A full-size viola's body is between and longer than the body of a full-size violin , with an average...
. Twinn married Rosamund Case, whom he had met at Bletchley Park
Bletchley Park
Bletchley Park is an estate located in the town of Bletchley, in Buckinghamshire, England, which currently houses the National Museum of Computing...
through his interest in music, in 1944; they had a son and three daughters.
Publications
- Peter F. G. Twinn and P. T. Harding, "Provisional atlas of the longhorn beetles (Coleoptera, Cerambycidae) of Britain", Huntingdon: Biological Records Centre, 1999. ISBN 1-870393-43-0