Leo Marks at the opening of the Violette Szabo Museum, Wormelow

Leopold Samuel Marks (September 24, 1920 - January 15, 2001) was an English cryptographer and scriptwriter. Image File history File links Leo Marks at the Violette Szabo museum This work is copyrighted. ... Violette Reine Elizabeth Bushell Szabo, G.C., M.B.E., CdG (June 26, 1921 – February 5?, 1945) was a World War II secret agent. ... September 24 is the 267th day of the year (268th in leap years). ... 1920 (MCMXX) is a leap year starting on Thursday (link will take you to calendar) // Events January January 7 - Forces of Russian White admiral Kolchak surrender in Krasnoyarsk. ... January 15 is the 15th day of the year in the Gregorian calendar. ... 2001: A Space Odyssey. ... Royal motto (French): Dieu et mon droit (Translated: God and my right) Englands location within the UK Official language English de facto Capital London de facto Largest city London Area – Total Ranked 1st UK 130,395 km² Population – Total (mid-2004) – Total (2001 Census) – Density Ranked 1st UK 50. ... Pre-19th century Leone Battista Alberti, polymath/universal genius, inventor of polyalphabetic substitution (see frequency analysis for the significance of this -- missed by most for a long time and dumbed down in the Vigenère cipher), and what may have been the first mechanical encryption aid. ... This list is poorly defined, permanently incomplete, or has become unverifiable or an indiscriminate list or repository of loosely associated topics. ...

Early life

Born the son of an antiquarian bookseller in London, he was first introduced to cryptography when his father showed him a copy of Edgar Allan Poe's story, The Gold Bug. From this early interest, he demonstrated his skill at codebreaking at an early age by deciphering his father's secret price codes. London is the capital city of the United Kingdom and of England. ... Cryptography has had a long and colourful history. ... This daguerreotype of Poe was taken less than a year before his death at the age of 40. ... The Gold Bug is a short story by one of the masters of the genre, Edgar Allan Poe. ... 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. ...

His father, Benjamin Marks, owned the Marks & Co. bookshop at 84 Charing Cross Road which featured in the 1970 book by Helene Hanff and the 1987 movie of the same title. 84, Charing Cross Road is the title of a book by Helene Hanff, published in 1970 about the long correspondence (1949-1969) between Hanff, a resident of New York City, and Frank Doel of the Marks & Co. ... 1970 (MCMLXX) was a common year starting on Thursday. ... Helene Hanff was an American writer; born Philadelphia, Pennsylvania, April 15, 1916; died New York, New York, April 9, 1997. ... 1987 (MCMLXXXVII) is a common year starting on Thursday of the Gregorian calendar. ...

As a teenager, he earned pocket money by setting the Times crossword. The Times is a national newspaper published daily in the United Kingdom. ... Cryptic crosswords are a particular type of crossword which have become widely popular in the UK, and several other Commonwealth nations such as Australia, New Zealand and India. ...

Work in cryptography

Marks joined the Armed Services in January 1942, and went to Bedford to train as a cryptographer. His original and unorthodox mode of thought led to him being the only one of his class judged not good enough to be sent to Bletchley Park; instead, he was sent to a rival organisation of the intelligence services, the recently formed Special Operations Executive (SOE). When his abilities subsequently became evident, he was referred to by Bletchley Park as "one that got away". Bedford is the county town of the English county of Bedfordshire. ... During World War II, British and American cryptographers at Bletchley Park broke a large number of Axis codes and ciphers, including the German Enigma machine. ... The Special Operations Executive (SOE), often called the Baker Street Irregulars after Sherlock Holmess fictional group of spies, was a World War II organisation initiated by Winston Churchill and Hugh Dalton in July 1940 as a mechanism for conducting warfare by means other than direct military engagement. ...

Marks personally briefed many of the Allied agents being sent into occupied Europe, including Noor Inayat Khan, and his own close friend, the legendary White Rabbit, 'Tommy' Yeo-Thomas. A highly empathetic and imaginative personality (as well as a self-professed "coward"), Marks continually acted on the rarely expressed premise that agents in occupied territories deserved every conceivable bit of support that those enjoying safety and freedom could provide. An attitude which is only just, considering their contribution to freedom and a level of personal sacrifice that would make most veteran soldiers feel humble, yet an attitude which is not always common among individuals, still less among bureaucracies. Noor Inyat Khan (January 1, 1914 - September 11, 1944) was born of an Indian father (Inayat Khan) and an American mother (Ora Ray Baker, who was a relative of Mary Baker Eddy, founder of Christian Science). ... Wing Commander Forest Frederick Edward Yeo-Thomas, G.C., Croix de Guerre (with palms), Insignia of the Commandeur of the Légion dHonneur, (June 17, 1901 - February 26, 1964) was the British Special Operations Executive (SOE) agent codenamed The White Rabbit during World War II. His particular sphere of...

Although personally in charge only of agent codes, by making a habit of walking into bureaucratic lion's dens, the young and "cowardly" Mr. Marks saved lives in the field. One of his first challenges (stubbornly resisted by the establishment) was to phase out the use of double transposition ciphers using keys based on preselected poems. These poem ciphers had the limited advantage of being easy to memorise, but a number of significant disadvantages, including limited cryptographic security, substantial minimum message sizes (short ones were hopelessly easy to crack.), and the fact that the complexity of using them caused a significant number of encoding errors to be made resulting in garbled messages. In classical cryptography, a transposition cipher changes one character from the plaintext to another (to decrypt the reverse is done). ... A key is a piece of information that controls the operation of a cryptography algorithm. ... Poetry (ancient Greek: poieo = create) is an art form in which human language is used for its aesthetic qualities in addition to, or instead of, its notional and semantic content. ... The poem code is a simple, and insecure, cryptographic method. ...

Cryptographic security was greatly enhanced by Marks' innovations, the "letter one-time pad" and one-time keys. While attempting to relegate poem codes to emergency use only, he enhanced their security by promoting the use of original poems in preference to widely known ones, thus forcing a would-be cracker to work it out the hard way for each message instead of being able to guess an agent's entire set of keys after breaking the key to a single message (or possibly even just part of the key.) Something of a poet himself, Marks wrote and gave to the agent Violette Szabo, the poignant The Life That I Have, which was also used in the 1958 film about her, Carve Her Name With Pride. Excerpt from a one time pad. ... Violette Reine Elizabeth Bushell Szabo, G.C., M.B.E., CdG (June 26, 1921 – February 5?, 1945) was a World War II secret agent. ... The Life That I Have was written by Leo Marks after the death of his fiancee in a plane crash. ... 1958 (MCMLVIII) was a common year starting on Wednesday of the Gregorian calendar. ... Carve Her Name with Pride is a 1958 British motion picture drama. ...

Gestapo signal tracers made clandestine radio operators an especially endangered species (life expectancy averaged about three weeks), so shorter and less frequent transmissions were the greatest gift a codemaster had to bestow. Being human and under pressure agents frequently made mistakes encoding messages, and the old practice was for the home station to tell them to recode it (usually a reasonably safe activity) and retransmit it (very dangerous, increasingly so the longer it takes.) In response to this problem Marks established, staffed, and trained a large group (based at Grendon Underwood, Buckinghamshire) to cryptanalyse garbled messages ("indecipherables") so that they could be dealt with in England without forcing the agent to run the risk of retransmission from the field. Other innovations of his simplified encoding in the field which reduced errors, and also made shorter messages possible, both of which reduced transmission time. The Deaths Head emblem similar to Skull and crossbones, often used as the insignia of the Gestapo The ▶ (help· info) (acronym of Geheime Staatspolizei; secret state police) was the official secret police of Nazi Germany. ... Grendon Underwood is a village in Buckinghamshire, England. ... Map of Bucks (1904) Buckinghamshire (abbreviated Bucks) is a county in South East England. ... 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. ...

The Germans generally didn't just murder captured radio operators out of hand. The goal was to "turn" and use them, or at least to extract enough information to be able to convincingly imitate them. For the safety of entire underground "circuits" it was important to be able to determine if a given operator was genuine and still free, and existing means of independently checking were primitive. When, due to the unusual lack of transcription errors in messages from agents in Holland, Marks became increasingly convinced (but not able to "prove" it) that the situation in the Netherlands was completely out of SOE's control and that they were being toyed with by the Germans (who among themselves actually did call it a game - Das Englandspiel), he was repeatedly told (for basically political reasons) to keep his mouth shut while as many as fifty agents were delivered directly to the Gestapo. The other side of this story was published in 1953 by Marks' German "opposite number" in Holland, H J Giskes in London Calling North Pole.

After SOE

He left SOE in 1946 and declined an offer of employment from the Secret Intelligence Service (SIS). He went on to write a number of marginally successful plays and films, including The Girl Who Couldn't Quite (1947), Cloudburst (1951), The Best Damn Lie (1957), Sebastian (1967) and Twisted Nerve (1968). Marks also wrote the script for Michael Powell's intelligent and highly controversial Peeping Tom (1960), the story of a serial killer who films his victims while stabbing them to death. Marks also provided the voice of the Devil in Martin Scorsese's The Last Temptation of Christ (1988). 1946 (MCMXLVI) was a common year starting on Tuesday. ... The Secret Intelligence Service (SIS), more commonly known as MI6 (originally Military Intelligence Section 6), or the Secret Service or simply Six, is the United Kingdoms external security agency. ... 1947 (MCMXLVII) was a common year starting on Wednesday (link will take you to calendar). ... A cloudburst is extreme rainfall, sometimes mixed with hail and thunder, which normally lasts no longer than a few minutes but is capable of creating minor flood conditions. ... :-* 1951 (MCMLI) was a common year starting on Monday; see its calendar. ... 1957 (MCMLVII) was a common year starting on Tuesday of the Gregorian calendar. ... Saint Sebastian (d. ... 1967 (MCMLXVII) was a common year starting on Sunday of the Gregorian calendar. ... Twisted Nerve is a 1969 film about a disturbed young man, Martin, whose mother treats like a small boy. ... 1968 (MCMLXVIII) was a leap year starting on Monday (the link is to a full 1968 calendar). ... Michael Powell film-maker. ... Peeping Tom is a 1960 psychological horror film by the British film director Michael Powell. ... 1960 (MCMLX) was a leap year starting on Friday (link will take you to calendar). ... Serial killers are individuals who have a history of multiple slayings of victims who were usually unknown to them beforehand. ... The Devil is the name given to a supernatural entity, who, in most Western religions, is the central embodiment of evil. ... Martin Scorsese at Cannes in 2002 Martin Scorsese (pronounced as Scor-SEH-see) (born November 17, 1942 in Queens, New York, USA) is a multi-Oscar nominated American film director. ... The Last Temptation of Christ is a novel written by Nikos Kazantzakis, first published in December 1960. ... 1988 (MCMLXXXVIII) was a leap year starting on a Friday of the Gregorian calendar. ...

In 1998, Marks published a book about his work in SOE — Between Silk and Cyanide: A Codemaker's Story 1941-1945. The book was reportedly written in the early 1980s, but didn't receive the UK Government's approval for publication until 1998. 1998 (MCMXCVIII) is a common year starting on Thursday of the Gregorian calendar, and was designated the International Year of the Ocean. ... The 1980s decade refers to the years from 1980 to 1989, inclusive. ... The United Kingdom is a unitary state and a democratic constitutional monarchy. ... 1998 (MCMXCVIII) is a common year starting on Thursday of the Gregorian calendar, and was designated the International Year of the Ocean. ...

He married the portrait painter Elena Gaussen in 1966, a marriage that lasted until shortly before his death in January 2001. Elena Gaussen is a portrait painter, formerly married to ex-cryptographer and screenwriter Leo Marks (1966-2000). ... 1966 (MCMLXVI) was a common year starting on Saturday (link goes to calendar) // Events January January 1 - In a coup, Colonel Jean-Bédel Bokassa ousts president David Dacko and takes over the Central African Republic. ... 2001: A Space Odyssey. ...

References

• Leo Marks, Between Silk and Cyanide: A Codemaker's Story 1941-1945. (HarperCollins, 1998). ISBN 068486780X.
• Philippe Ganier-Raymond, The Tangled Web, (Arthur Barker 1968, Warner Paperback ISBN 0446659347, originally published in French as Le Réseau Éntranglé) one of the central stories in Marks' book, the betrayal of the SOE Dutch network, told from the Dutch and German points of view.

External links

• Leo Marks at the Powell & Pressburger pages