British Film Institute
The British Film Institute is a film and charitable organisation which promotes and preserves filmmaking and television in the United Kingdom. It was established by Royal Charter to: Encourage the development of the arts of film and the moving image throughout the United Kingdom, to promote their use as a record of contemporary life and manners, to promote education about film and the moving image and their impact on society, to promote access to and appreciation of the widest possible range of British and world cinema and to establish, care for and develop collections reflecting the moving image history and heritage of the United Kingdom; the BFI maintains the world's largest film archive, the BFI National Archive called National Film Library, National Film Archive, National Film and Television Archive. The archive contains more than 50,000 fiction films, over 100,000 non-fiction titles, around 625,000 television programmes; the majority of the collection is British material but it features internationally significant holdings from around the world.
The Archive collects films which feature key British actors and the work of British directors. The BFI runs the BFI Southbank and London IMAX cinema, both located on the south bank of the River Thames in London; the IMAX has the largest cinema screen in the UK and shows popular recent releases and short films showcasing its technology, which includes 3D screenings and 11,600 watts of digital surround sound. BFI Southbank shows films from all over the world critically acclaimed historical & specialised films that may not otherwise get a cinema showing; the BFI distributes archival and cultural cinema to other venues – each year to more than 800 venues all across the UK, as well as to a substantial number of overseas venues. The BFI offers a range of education initiatives, in particular to support the teaching of film and media studies in schools. In late 2012, the BFI received money from the Department For Education to create the BFI Film Academy Network; the BFI runs the annual London Film Festival along with BFI Flare: London LGBT Film Festival and the youth-orientated Future Film Festival.
The BFI publishes the monthly Sound magazine as well as films on Blu-ray, DVD and books. It runs the BFI National Library, maintains the BFI Film & TV Database and Summary of Information on Film and Television, which are databases of credits and other information about film and television productions. SIFT has a collection of about 7 million still frames from television; the BFI has co-produced a number of television series featuring footage from the BFI National Archive, in partnership with the BBC, including The Lost World of Mitchell & Kenyon, The Lost World of Friese-Greene, The Lost World of Tibet. The institute was founded in 1933. Despite its foundation resulting from a recommendation in a report on Film in National Life, at that time the institute was a private company, though it has received public money throughout its history—from the Privy Council and Treasury until 1965 and the various culture departments since then; the institute was restructured following the Radcliffe Report of 1948 which recommended that it should concentrate on developing the appreciation of filmic art, rather than creating film itself.
Thus control of educational film production passed to the National Committee for Visual Aids in Education and the British Film Academy assumed control for promoting production. From 1952–2000, the BFI provided funding for new and experimental filmmakers via the BFI Production Board; the institute received a Royal Charter in 1983. This was updated in 2000, in the same year the newly established UK Film Council took responsibility for providing the BFI's annual grant-in-aid; as an independent registered charity, the BFI is regulated by the Charity Commission and the Privy Council. In 1988, the BFI opened the London Museum of the Moving Image on the South Bank. MOMI was acclaimed internationally and set new standards for education through entertainment, but subsequently it did not receive the high levels of continuing investment that might have enabled it to keep pace with technological developments and ever-rising audience expectations; the Museum was "temporarily" closed in 1999. This did not happen, MOMI's closure became permanent in 2002 when it was decided to redevelop the South Bank site.
This redevelopment was itself further delayed. The BFI is managed on a day-to-day basis by its chief executive, Amanda Nevill. Supreme decision-making authority rests with a board of up to 14 governors; the current chair is Josh Berger, who took up the post in February 2016. He succeeded Greg Dyke, who took office on 1 March 2008. Dyke succeeded the late Anthony Minghella, chair from 2003 until 31 December 2007; the chair of the board is appointed by the BFI's own Board of Governors but requires the consent of the Secretary of State for Culture and Sport. Other Governors are co-opted by existing board members; the BFI operates with three sources of income. The largest is public money allocated by the Department for Culture and Sport. In 2011–12, this funding amounted to £20m; the second largest source is commercial activity such as receipts from ticket sales at BFI Southbank or the BFI London IMAX theatre, sales of DVDs, etc. Thirdly and sponsorship of around £5m
HarperCollins Publishers L. L. C. is one of the world's largest publishing companies and is one of the Big Five English-language publishing companies, alongside Hachette, Penguin Random House, Simon & Schuster. The company is a subsidiary of News Corp.. The name is a combination of several publishing firm names: Harper & Row, an American publishing company acquired in 1987, together with UK publishing company William Collins, acquired in 1990; the worldwide CEO of HarperCollins is Brian Murray. HarperCollins has publishing groups in the United States, the United Kingdom, New Zealand and China; the company publishes many different imprints, both former independent publishing houses and new imprints. In 1989, Collins was bought by Rupert Murdoch's News Corporation, the publisher was combined with Harper & Row, which NewsCorp had acquired two years earlier. In addition to the simplified and merged name, the logo for HarperCollins was derived from the torch logo for Harper and Row, the fountain logo for Collins, which were combined into a stylized set of flames atop waves.
In 1999, News Corporation purchased the Hearst Book Group, consisting of William Morrow & Company and Avon Books. These imprints are now published under the rubric of HarperCollins. HarperCollins bought educational publisher Letts and Lonsdale in March 2010. In 2011, HarperCollins announced; the purchase was completed on July 11, 2012, with an announcement that Thomas Nelson would operate independently given the position it has in Christian book publishing. Both Thomas Nelson and Zondervan were organized as imprints, or "keystone publishing programs," under a new division, HarperCollins Christian Publishing. Key roles in the reorganization were awarded to former Thomas Nelson executives. In 2012, HarperCollins acquired part of the trade operations of John Son in Canada. In 2014, HarperCollins acquired Canadian romance publisher Harlequin Enterprises for C$455 million. Brian Murray, the current CEO of HarperCollins, succeeded Jane Friedman, CEO from 1997 to 2008. Notable management figures include Lisa Sharkey, current senior vice president and director of creative development and Barry Winkleman from 1989 to 1994.
In April 2012, the United States Department of Justice filed United States v. Apple Inc. naming Apple, HarperCollins, four other major publishers as defendants. The suit alleged that they conspired to fix prices for e-books, weaken Amazon.com's position in the market, in violation of antitrust law. In December 2013, a federal judge approved a settlement of the antitrust claims, in which HarperCollins and the other publishers paid into a fund that provided credits to customers who had overpaid for books due to the price-fixing, it was announced to employees and later in the day on November 5, 2012, that HarperCollins was closing its remaining two U. S. warehouses, in order to merge shipping and warehousing operations with R. R. Donnelley in Indiana; the Scranton, PA warehouse closed in September 2013 and a Nashville, TN warehouse, under the name Thomas Nelson, in the winter of 2013. Several office positions and departments continued to work for HarperCollins in Scranton, but in a new location.
The Scranton warehouse closing eliminated 200 jobs, the Nashville warehouse closing eliminated up to 500 jobs. HarperCollins closed 2 U. S. warehouses, one in Williamsport, PA in 2011 and another in Grand Rapids, MI in 2012. “We have taken a long-term, global view of our print distribution and are committed to offering the broadest possible reach for our authors," said HarperCollins Chief Executive Brian Murray, according to Publishers Weekly."We are retooling the traditional distribution model to ensure we can competitively offer the entire HarperCollins catalog to customers regardless of location.” Company officials attribute the closings and mergers to the growing demand for e-book formats and the decline in print purchasing. HarperCollins maintains the backlist of many of the books published by their many merged imprints, in addition to having picked up new authors since the merger. Authors published by Harper include Mark Twain, the Brontë sisters and William Makepeace Thackeray. Authors published by Collins include H. G. Wells and Agatha Christie.
HarperCollins acquired the publishing rights to J. R. R. Tolkien's work in 1990 when Unwin Hymen was bought; this is a list of some of the more noted books, series, published by HarperCollins and their various imprints and merged publishing houses. The Hobbit, J. R. R. Tolkien The Lord of the Rings, J. R. R. Tolkien The Art of Loving, Erich Fromm Master and Commander, Patrick O'Brian the Leaphorn and Chee books, Tony Hillerman The Silmarillion, J. R. R. Tolkien Collins English Dictionary, a major dictionary Sharpe series, Bernard Cornwell Frida: A Biography of Frida Kahlo, Hayden Herrera, adapted into the 2002 film Frida The History of Middle-earth series, J. R. R. Tolkien Weaveworld, Clive Barker the Paladin Poetry Series Of Gravity & Angels, Jane Hirshfield The
World War II
World War II known as the Second World War, was a global war that lasted from 1939 to 1945. The vast majority of the world's countries—including all the great powers—eventually formed two opposing military alliances: the Allies and the Axis. A state of total war emerged, directly involving more than 100 million people from over 30 countries; the major participants threw their entire economic and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. World War II was the deadliest conflict in human history, marked by 50 to 85 million fatalities, most of whom were civilians in the Soviet Union and China, it included massacres, the genocide of the Holocaust, strategic bombing, premeditated death from starvation and disease, the only use of nuclear weapons in war. Japan, which aimed to dominate Asia and the Pacific, was at war with China by 1937, though neither side had declared war on the other. World War II is said to have begun on 1 September 1939, with the invasion of Poland by Germany and subsequent declarations of war on Germany by France and the United Kingdom.
From late 1939 to early 1941, in a series of campaigns and treaties, Germany conquered or controlled much of continental Europe, formed the Axis alliance with Italy and Japan. Under the Molotov–Ribbentrop Pact of August 1939, Germany and the Soviet Union partitioned and annexed territories of their European neighbours, Finland and the Baltic states. Following the onset of campaigns in North Africa and East Africa, the fall of France in mid 1940, the war continued between the European Axis powers and the British Empire. War in the Balkans, the aerial Battle of Britain, the Blitz, the long Battle of the Atlantic followed. On 22 June 1941, the European Axis powers launched an invasion of the Soviet Union, opening the largest land theatre of war in history; this Eastern Front trapped most crucially the German Wehrmacht, into a war of attrition. In December 1941, Japan launched a surprise attack on the United States as well as European colonies in the Pacific. Following an immediate U. S. declaration of war against Japan, supported by one from Great Britain, the European Axis powers declared war on the U.
S. in solidarity with their Japanese ally. Rapid Japanese conquests over much of the Western Pacific ensued, perceived by many in Asia as liberation from Western dominance and resulting in the support of several armies from defeated territories; the Axis advance in the Pacific halted in 1942. Key setbacks in 1943, which included a series of German defeats on the Eastern Front, the Allied invasions of Sicily and Italy, Allied victories in the Pacific, cost the Axis its initiative and forced it into strategic retreat on all fronts. In 1944, the Western Allies invaded German-occupied France, while the Soviet Union regained its territorial losses and turned toward Germany and its allies. During 1944 and 1945 the Japanese suffered major reverses in mainland Asia in Central China, South China and Burma, while the Allies crippled the Japanese Navy and captured key Western Pacific islands; the war in Europe concluded with an invasion of Germany by the Western Allies and the Soviet Union, culminating in the capture of Berlin by Soviet troops, the suicide of Adolf Hitler and the German unconditional surrender on 8 May 1945.
Following the Potsdam Declaration by the Allies on 26 July 1945 and the refusal of Japan to surrender under its terms, the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki on 6 and 9 August respectively. With an invasion of the Japanese archipelago imminent, the possibility of additional atomic bombings, the Soviet entry into the war against Japan and its invasion of Manchuria, Japan announced its intention to surrender on 15 August 1945, cementing total victory in Asia for the Allies. Tribunals were set up by fiat by the Allies and war crimes trials were conducted in the wake of the war both against the Germans and the Japanese. World War II changed the political social structure of the globe; the United Nations was established to foster international co-operation and prevent future conflicts. The Soviet Union and United States emerged as rival superpowers, setting the stage for the nearly half-century long Cold War. In the wake of European devastation, the influence of its great powers waned, triggering the decolonisation of Africa and Asia.
Most countries whose industries had been damaged moved towards economic expansion. Political integration in Europe, emerged as an effort to end pre-war enmities and create a common identity; the start of the war in Europe is held to be 1 September 1939, beginning with the German invasion of Poland. The dates for the beginning of war in the Pacific include the start of the Second Sino-Japanese War on 7 July 1937, or the Japanese invasion of Manchuria on 19 September 1931. Others follow the British historian A. J. P. Taylor, who held that the Sino-Japanese War and war in Europe and its colonies occurred and the two wars merged in 1941; this article uses the conventional dating. Other starting dates sometimes used for World War II include the Italian invasion of Abyssinia on 3 October 1935; the British historian Antony Beevor views the beginning of World War II as the Battles of Khalkhin Gol fought between Japan and the fo
Special Operations Executive
The Special Operations Executive was a British World War II organisation. It was formed on 22 July 1940 under Minister of Economic Warfare Hugh Dalton, from the amalgamation of three existing secret organisations, its purpose was to conduct espionage and reconnaissance in occupied Europe against the Axis powers, to aid local resistance movements. Few people were aware of SOE's existence; those who were part of it or liaised with it were sometimes referred to as the "Baker Street Irregulars", after the location of its London headquarters. It was known as "Churchill's Secret Army" or the "Ministry of Ungentlemanly Warfare", its various branches, sometimes the organisation as a whole, were concealed for security purposes behind names such as the "Joint Technical Board" or the "Inter-Service Research Bureau", or fictitious branches of the Air Ministry, Admiralty or War Office. SOE operated in all territories occupied or attacked by the Axis forces, except where demarcation lines were agreed with Britain's principal Allies.
It made use of neutral territory on occasion, or made plans and preparations in case neutral countries were attacked by the Axis. The organisation directly employed or controlled more than 13,000 people, about 3,200 of whom were women. After the war, the organisation was dissolved on 15 January 1946. A memorial to SOE's agents was unveiled in October 2009 on the Albert Embankment by Lambeth Palace in London; the organisation was formed from the merger of three existing secret departments, formed shortly before the outbreak of the Second World War. After Germany annexed Austria in March 1938, the Foreign Office created a propaganda organisation known as Department EH, run by Canadian newspaper magnate Sir Campbell Stuart; that month, the Secret Intelligence Service formed a section known as Section D, under Major Lawrence Grand RE, to investigate the use of sabotage and other irregular means to weaken an enemy. In the autumn of the same year, the War Office expanded an existing research department known as GS and appointed Major J. C. Holland RE as its head to conduct research into guerrilla warfare.
GS was renamed MI in early 1939. These three departments worked with few resources until the outbreak of war. There was much overlap between their activities. Section D and EH duplicated much of each other's work. On the other hand, the heads of Section D and MI knew shared information, they agreed to a rough division of their activities. During the early months of the war, Section D was based first at St Ermin's Hotel in Westminster and the Metropole Hotel near Trafalgar Square; the Section attempted unsuccessfully to sabotage deliveries of vital strategic materials to Germany from neutral countries by mining the Iron Gate on the River Danube. MI meanwhile produced technical handbooks for guerrilla leaders. MI was involved in the formation of the Independent Companies, autonomous units intended to carry out sabotage and guerrilla operations behind enemy lines in the Norwegian Campaign, the Auxiliary Units, stay-behind commando units based on the Home Guard which would act in the event of an Axis invasion of Britain, as seemed possible in the early years of the war.
On 13 June 1940, at the instigation of newly appointed Prime Minister Winston Churchill, Lord Hankey persuaded Section D and MI that their operations should be coordinated. On 1 July, a Cabinet level meeting arranged the formation of a single sabotage organisation. On 16 July, Hugh Dalton, the Minister of Economic Warfare, was appointed to take political responsibility for the new organisation, formally created on 22 July 1940. Dalton recorded in his diary that on that day the War Cabinet agreed to his new duties and that Churchill had told him, "And now go and set Europe ablaze." Dalton used the Irish Republican Army during the Irish War of Independence as a model for the organisation. Sir Frank Nelson was nominated by SIS to be director of the new organisation, a senior civil servant, Gladwyn Jebb, transferred from the Foreign Office to it, with the title of Chief Executive Officer. Campbell Stuart left the organisation, the flamboyant Major Grand was returned to the regular army. At his own request, Major Holland left to take up a regular appointment in the Royal Engineers.
However, Holland's former deputy at MI, Brigadier Colin Gubbins, returned from command of the Auxiliary Units to be Director of Operations of SOE. One department of MI, MI R, involved in the development of weapons for irregular warfare, was not formally integrated into SOE but became an independent body codenamed MD1. Directed by Major Millis Jefferis, it was located at The Firs in Whitchurch and nicknamed "Churchill's Toyshop" from the Prime Minister's close interest in it and his enthusiastic support; the director of SOE was referred to by the initials "CD". Nelson, the first director to be appointed, was a former head of a trading firm in India, a back bench Conservative Member of Parliament and Consul in Basel, Switzerland. There he had been engaged in undercover intelligence work. In February 1942 Dalton became President of the Board of Trade and was replaced as Minister of Economic Warfare by Lord Selborne. Selborne in turn retired Nelson, who had s
National Socialism, more known as Nazism, is the ideology and practices associated with the Nazi Party – the National Socialist German Workers' Party – in Nazi Germany, of other far-right groups with similar aims. Nazism is a form of fascism and showed that ideology's disdain for liberal democracy and the parliamentary system, but incorporated fervent antisemitism, anti-communism, scientific racism, eugenics into its creed, its extreme nationalism came from Pan-Germanism and the Völkisch movement prominent in the German nationalism of the time, it was influenced by the Freikorps paramilitary groups that emerged after Germany's defeat in World War I, from which came the party's "cult of violence", "at the heart of the movement."Nazism subscribed to theories of racial hierarchy and Social Darwinism, identifying the Germans as a part of what the Nazis regarded as an Aryan or Nordic master race. It aimed to overcome social divisions and create a German homogeneous society based on racial purity which represented a people's community.
The Nazis aimed to unite all Germans living in German territory, as well as gain additional lands for German expansion under the doctrine of Lebensraum and exclude those who they deemed either community aliens or "inferior" races. The term "National Socialism" arose out of attempts to create a nationalist redefinition of "socialism", as an alternative to both Marxist international socialism and free market capitalism. Nazism rejected the Marxist concepts of class conflict and universal equality, opposed cosmopolitan internationalism, sought to convince all parts of the new German society to subordinate their personal interests to the "common good", accepting political interests as the main priority of economic organization; the Nazi Party's precursor, the Pan-German nationalist and antisemitic German Workers' Party, was founded on 5 January 1919. By the early 1920s the party was renamed the National Socialist German Workers' Party – to attract workers away from left-wing parties such as the Social Democrats and the Communists – and Adolf Hitler assumed control of the organization.
The National Socialist Program or "25 Points" was adopted in 1920 and called for a united Greater Germany that would deny citizenship to Jews or those of Jewish descent, while supporting land reform and the nationalization of some industries. In Mein Kampf, Hitler outlined the anti-Semitism and anti-Communism at the heart of his political philosophy, as well as his disdain for representative democracy and his belief in Germany's right to territorial expansion; the Nazi Party won the greatest share of the popular vote in the two Reichstag general elections of 1932, making them the largest party in the legislature by far, but still short of an outright majority. Because none of the parties were willing or able to put together a coalition government, in 1933 Hitler was appointed Chancellor of Germany by President Paul Von Hindenburg, through the support and connivance of traditional conservative nationalists who believed that they could control him and his party. Through the use of emergency presidential decrees by Hindenburg, a change in the Weimar Constitution which allowed the Cabinet to rule by direct decree, bypassing both Hindenburg and the Reichstag, the Nazis had soon established a one-party state.
The Sturmabteilung and the Schutzstaffel functioned as the paramilitary organizations of the Nazi Party. Using the SS for the task, Hitler purged the party's more and economically radical factions in the mid-1934 Night of the Long Knives, including the leadership of the SA. After the death of President Hindenburg, political power was concentrated in Hitler's hands and he became Germany's head of state as well as the head of the government, with the title of Führer, meaning "leader". From that point, Hitler was the dictator of Nazi Germany, known as the "Third Reich", under which Jews, political opponents and other "undesirable" elements were marginalized, imprisoned or murdered. Many millions of people were exterminated in a genocide which became known as the Holocaust during World War II, including around two-thirds of the Jewish population of Europe. Following Germany's defeat in World War II and the discovery of the full extent of the Holocaust, Nazi ideology became universally disgraced.
It is regarded as immoral and evil, with only a few fringe racist groups referred to as neo-Nazis, describing themselves as followers of National Socialism. The full name of the party was Nationalsozialistische Deutsche Arbeiterpartei for which they used the acronym NSDAP; the term "Nazi" was in use before the rise of the NSDAP as a colloquial and derogatory word for a backwards farmer or peasant, characterizing an awkward and clumsy person. In this sense, the word Nazi was a hypocorism of the German male name Ignatz – Ignatz being a common name at the time in Bavaria, the area from which the NSDAP emerged. In the 1920s, political opponents of the NSDAP in the German labour movement seized on this and – using the earlier abbreviated term "Sozi" for Sozialist as an example – shortened NSDAP's name, Nationalsozialistische, to the dismissive "Nazi", in order to associate them with the derogatory use of the term mentioned above; the first use of the term "Nazi" by the National Socialists occurred in 1926 in a publication by Joseph Goebbels called Der Nazi-Sozi.
In Goebbels' pamphlet, the word "Nazi" only appears when linked with the word "Sozi" as an abbreviation of
Cryptanalysis is the study of analyzing information systems in order to study the hidden aspects of the systems. Cryptanalysis is used to breach cryptographic security systems and gain access to the contents of encrypted messages if the cryptographic key is unknown. In addition to mathematical analysis of cryptographic algorithms, cryptanalysis includes the study of side-channel attacks that do not target weaknesses in the cryptographic algorithms themselves, but instead exploit weaknesses in their implementation. Though the goal has been the same, the methods and techniques of cryptanalysis have changed drastically through the history of cryptography, adapting to increasing cryptographic complexity, ranging from the pen-and-paper methods of the past, through machines like the British Bombes and Colossus computers at Bletchley Park in World War II, to the mathematically advanced computerized schemes of the present. Methods for breaking modern cryptosystems involve solving constructed problems in pure mathematics, the best-known being integer factorization.
Given some encrypted data, the goal of the cryptanalyst is to gain as much information as possible about the original, unencrypted data. It is useful to consider two aspects of achieving this; the first is breaking the system —, discovering how the encipherment process works. The second is solving the key, unique for a particular encrypted message or group of messages. Attacks can be classified based on; as a basic starting point it is assumed that, for the purposes of analysis, the general algorithm is known. This is a reasonable assumption in practice — throughout history, there are countless examples of secret algorithms falling into wider knowledge, variously through espionage and reverse engineering.: Ciphertext-only: the cryptanalyst has access only to a collection of ciphertexts or codetexts. Known-plaintext: the attacker has a set of ciphertexts to which he knows the corresponding plaintext. Chosen-plaintext: the attacker can obtain the ciphertexts corresponding to an arbitrary set of plaintexts of his own choosing.
Adaptive chosen-plaintext: like a chosen-plaintext attack, except the attacker can choose subsequent plaintexts based on information learned from previous encryptions. Adaptive chosen ciphertext attack. Related-key attack: Like a chosen-plaintext attack, except the attacker can obtain ciphertexts encrypted under two different keys; the keys are unknown. Attacks can be characterised by the resources they require; those resources include: Time -- the number of computation steps. Memory — the amount of storage required to perform the attack. Data — the quantity and type of plaintexts and ciphertexts required for a particular approach. It's sometimes difficult to predict these quantities especially when the attack isn't practical to implement for testing, but academic cryptanalysts tend to provide at least the estimated order of magnitude of their attacks' difficulty, for example, "SHA-1 collisions now 252."Bruce Schneier notes that computationally impractical attacks can be considered breaks: "Breaking a cipher means finding a weakness in the cipher that can be exploited with a complexity less than brute force.
Never mind that brute-force might require 2128 encryptions. The results of cryptanalysis can vary in usefulness. For example, cryptographer Lars Knudsen classified various types of attack on block ciphers according to the amount and quality of secret information, discovered: Total break — the attacker deduces the secret key. Global deduction — the attacker discovers a functionally equivalent algorithm for encryption and decryption, but without learning the key. Instance deduction — the attacker discovers additional plaintexts not known. Information deduction — the attacker gains some Shannon information about plaintexts not known. Distinguishing algorithm — the attacker can distinguish the cipher from a random permutation. Academic attacks are against weakened versions of a cryptosystem, such as a block cipher or hash function with some rounds removed. Many, but not all, attacks become exponentially more difficult to execute as rounds are added to a cryptosystem, so it's possible for the full cryptosystem to be strong though reduced-round variants are weak.
Nonetheless, partial breaks that come close to breaking the original cryptosystem may mean that a full break will follow. In academic cryptography, a weakness or a break in a scheme is defined quite conservatively: it might require impractical amounts of time, memory, or known plaintexts, it might require the attacker be able to do things many real-world attackers can't: for example, the attacker may need to choose particular plaintexts to be encrypted or to ask for plaintexts to be encrypted using several keys related to the secret key. Furthermore
Leopold Samuel "Leo" Marks, MBE was an English writer and cryptographer. During the Second World War he headed the codes office supporting resistance agents in occupied Europe for the secret Special Operations Executive organisation. After the war, Marks became a playwright and screenwriter, writing scripts that utilised his war-time cryptographic experiences, he wrote the script for Peeping Tom, the controversial film directed by Michael Powell which had a disastrous effect on Powell's career, but was described by Martin Scorsese as a masterpiece. In 1998, towards the end of his life, Marks published a personal history of his experiences during the war, Between Silk and Cyanide, critical of the leadership of SOE. Marks was the son of Benjamin Marks, the joint owner of Marks & Co, an antiquarian bookseller in Charing Cross Road, London, he was introduced at an early age to cryptography when his father showed him Edgar Allan Poe's story, The Gold-Bug. From this early interest, he demonstrated his skill at codebreaking by deciphering the secret price codes which his father wrote inside the covers of books.
The bookshop subsequently became famous as a result of the book 84, Charing Cross Road, based on correspondence between American writer Helene Hanff and the shop's chief buyer, Frank Doel. Marks was conscripted in January 1942, trained as a cryptographer. Unlike the rest of his intake, who were sent to the main British codebreaking centre at Bletchley Park, Marks was regarded as a misfit and he was assigned the newly formed Special Operations Executive in Baker Street, set up to train agents to operate behind enemy lines in occupied Europe and to assist local resistance groups. SOE has been described as "a mixture of brilliant brains and bungling amateurs". Marks wrote that he had an inauspicious arrival at SOE when it took him all day to decipher a code he had been expected to finish in 20 minutes, not atypically, SOE had forgotten to supply the cipher key. Marks briefed many Allied agents sent into occupied Europe, including Noor Inayat Khan, the Grouse/Swallow team of four Norwegian Telemark saboteurs and his own close friend'Tommy' Yeo-Thomas, nicknamed "the White Rabbit".
In an interview which accompanied the DVD of the film Peeping Tom, Marks quoted General Eisenhower as saying that his group's work shortened the war by three months, saving countless lives. Marks was portrayed by Anton Lesser in David Morley's BBC Radio drama A Cold Supper Behind Harrods; the fiction play was inspired by conversations between Marks and David Morley and real events in SOE. It featured David Jason, Stephanie Cole as Vera Atkins. One of Marks's first challenges was to phase out double transposition ciphers using keys based on preselected poems; these poem ciphers had the limited advantage of being easy to memorise, but significant disadvantages, including limited cryptographic security, substantial minimum message sizes, the fact that the method's complexity caused encoding errors. Cryptographic security was enhanced by Marks's innovations "worked-out keys", he was credited with inventing the letter one-time pad, but while he did independently discover the method, he found it in use at Bletchley.
While attempting to relegate poem codes to emergency use, he enhanced their security by promoting the use of original poems in preference to known ones, forcing a cryptanalyst to work it out the hard way for each message instead of guessing an agent's entire set of keys after breaking the key to a single message Marks wrote many poems used by agents, the most famous being one he gave to the agent Violette Szabo, The Life That I Have, which gained popularity when it was used in the 1958 film about her, Carve Her Name With Pride. According to his book, Marks wrote the poem in Christmas 1943 about a girlfriend, who had died in an air crash in Canada; the life that I have Is all that I have And the life that I have Is yours. The love that I have Of the life that I have Is yours and yours. A sleep I shall have A rest I shall have Yet death will be but a pause. For the peace of my years In the long green grass Will be yours and yours. Gestapo signal tracers endangered clandestine radio operators, their life expectancy averaged about six weeks.
Therefore and less frequent transmissions from the codemaster were of value. The pressure could cause agents to make mistakes encoding messages, the practice was for the home station to tell them to recode it and retransmit it. In response to this problem, Marks established and trained a group based at Grendon Underwood, Buckinghamshire to cryptanalyse garbled messages so they could be dealt with in England without forcing the agent to risk retransmitting from the field. Other innovations of his simplified encoding in the field, which reduced errors and made shorter messages possible, both of which reduced transmission time; the Germans did not execute captured radio operators out of hand. The goal was to extract enough information to imitate them. For the safety of entire underground "circuits", it was important to determine if an operator was genuine and still free, but means of independently checking were primitive. Marks claims that he became convinced that their agents in the Netherlands had been compromised by the German count