Leopold Samuel Marks (24 September 1920 – 15 January 2001) was an English writer, screenwriter, 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 frequently utilised his war-time cryptographic experiences. He wrote the script for Peeping Tom, the controversial film directed by Michael Powell that had a disastrous effect on Powell's career, but was later 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, which was critical of the leadership of SOE.
Early life
Marks was born into a devout Jewish family. He 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 that his father wrote inside the covers of books.
Work in cryptography
Marks was conscripted into the British Army in January 1942 and trained as a cryptographer; apparently he demonstrated the ability to complete one week's work in decipherment exercise in a few hours. which was set up to train agents to operate behind enemy lines and to assist local resistance groups in occupied Europe. SOE has been described as "a mixture of brilliant brains and bungling amateurs".
Developments of cryptographic practice
One of Marks's first challenges was to phase out double transposition ciphers using keys based on poems. These poem ciphers had the limited advantage of being easy to memorise, but significant disadvantages,
Preference for original code poems
While attempting to relegate poem codes to emergency use, he enhanced their security by promoting the use of original poems in preference to widely 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 (or possibly just part of the key.) Marks wrote many poems later 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, Ruth, who had recently died in an air crash in Canada; supposedly the god-daughter of the head of SOE, Sir Charles Jocelyn Hambro.
<blockquote>
The life that I have<br />
Is all that I have<br />
And the life that I have<br />
Is yours.<br />
<br />
The love that I have<br />
Of the life that I have<br />
Is yours and yours and yours.<br />
<br />
A sleep I shall have<br />
A rest I shall have<br />
Yet death will be but a pause.<br />
<br />
For the peace of my years<br />
In the long green grass<br />
Will be yours and yours and yours.<br />
</blockquote>
Gestapo activities and "Indecipherables"
Gestapo signal tracers endangered clandestine radio operators, and their life expectancy in occupied France averaged about six weeks. Therefore, short and less frequent transmissions from the codemaster were of value. The pressure could cause agents to make mistakes encoding messages, and the practice was for the home station to tell them to recode it (usually a safe activity) and retransmit it (dangerous, and increasingly so the longer it took). In response to this problem, Marks established, staffed and trained a group based at Grendon Underwood, Buckinghamshire to cryptanalyse garbled messages ("indecipherables") 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.
"Das Englandspiel" in the Netherlands
The Germans generally did not execute captured radio operators out of hand. The goal was to turn and use them, or 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 (but was unable to prove) that their agents in the Netherlands had been compromised by the German counter-intelligence Abwehr.
Marks wrote the script for Michael Powell's film Peeping Tom (1960), the story of a serial killer who films his victims while stabbing them. The film provoked critical revulsion at the time, and was described as "evil and pornographic."
In 1998, Marks published his account of his work in SOE – Between Silk and Cyanide: A Codemaker's Story 1941–1945. The book was written in the early 1980s, but didn't receive UK Government approval for publication until 1998. She is a portrait artist noted for the silkscreen Dinner, Chelsea Arts Club, and the oil on canvas Russell Square, 1985 She studied at Southern College of Art, Portsmouth; Royal Academy Schools; and Camberwell School of Arts and Crafts.