William Frederick Friedman (September 24, 1891 – November 2, 1969) was a US Army cryptographer who ran the research division of the Army's Signal Intelligence Service (SIS) in the 1930s, and parts of its follow-on services into the 1950s. In 1940, subordinates of his led by Frank Rowlett broke Japan's PURPLE cipher, thus disclosing Japanese diplomatic secrets before America's entrance into World War II.

Early life

Friedman was born Wolf Friedman (, ), in Kishinev, Bessarabia, the son of Frederick Friedman, a Jew from Bucharest who worked as a translator and linguist for the Russian Postal Service, and the daughter of a well-to-do wine merchant. Friedman's family left Kishinev in 1892 on account of anti-Semitic persecution, ending up in Pittsburgh, Pennsylvania. Three years later, his first name was changed to William.

As a child, Friedman was introduced to cryptography in the short story "The Gold-Bug" by Edgar Allan Poe. He studied at the Michigan Agricultural College (known today as Michigan State University) in East Lansing and received a scholarship to work on genetics at Cornell University. Meanwhile, George Fabyan, who ran a private research laboratory to study any personally interesting project, decided to set up his own genetics project and was referred to Friedman. Friedman joined Fabyan's Riverbank Laboratories outside Chicago in September 1915. As head of the Department of Genetics, one of the projects he ran studied the effects of moonlight on crop growth, and so he experimented with the planting of wheat during various phases of the moon.

Initial work in cryptology

thumb|William and Elizebeth Friedman, recently married, at Riverbank in 1917

thumb|Riverbank Laboratories

Another of Fabyan's pet projects was research into secret messages which Sir Francis Bacon had allegedly hidden in various texts during the reigns of Elizabeth I and James I. The research was carried out by Elizabeth Wells Gallup. She believed that she had discovered many such messages in the works of William Shakespeare, and convinced herself that Bacon had written many, if not all, of Shakespeare's works. Friedman had become something of an expert photographer while working on his other projects, and was asked to travel to England on several occasions to help Gallup photograph historical manuscripts during her research. He became fascinated with the work as he courted Elizebeth Smith, Gallup's assistant and an accomplished cryptographer. They married, and he soon became director of Riverbank's Department of Codes and Ciphers as well as its Department of Genetics. During this time, Friedman wrote a series of eight papers on cryptography, collectively known as the "Riverbank Publications", including the first description of the index of coincidence, an important mathematical tool in cryptanalysis.

With the entry of the United States into World War I, Fabyan offered the services of his Department of Codes and Ciphers to the government. No Federal department existed for this kind of work (although both the Army and Navy had had embryonic departments at various times), and soon Riverbank became the unofficial cryptographic center for the US Government. During this period, the Friedmans broke a code used by German-funded Indian radicals in the US who planned to ship arms to India to gain independence from Britain.

National Security Agency

thumb|upright|left|Bust of Friedman on display at the [[National Cryptologic Museum, where he is identified as the "Dean of American Cryptology".]]

Following World War II, Friedman remained in government signals intelligence. In 1949 he became head of the cryptographic division of the newly formed Armed Forces Security Agency (AFSA) and in 1952 became chief cryptologist for the National Security Agency (NSA) when it was formed to take over from AFSA. Friedman produced a classic series of textbooks, "Military Cryptanalysis", which was used to train NSA students. (These were revised and extended, under the title "Military Cryptanalytics", by Friedman's assistant and successor Lambros D. Callimahos, and used to train many additional cryptanalysts.) During his early years at NSA, he encouraged it to develop what were probably the first super-computers, although he was never convinced a machine could have the "insight" of a human mind.

Friedman spent much of his free time trying to decipher the famous Voynich Manuscript, said to be written sometime between 1403–1437. However, after four decades of study he finally had to admit defeat, contributing no more than an educated guess as to its origins and meaning.

In 1955, Friedman initiated, on behalf of the NSA, a secret agreement with Crypto AG, a Swiss manufacturer of encryption machines. The agreement resulted in many of the company's machines being compromised, so that the messages produced by them became crackable by the NSA.

Friedman retired in 1956 and, with his wife, turned his attention to the problem that had originally brought them together: examining Bacon's supposed codes. Together they wrote a book entitled The Cryptologist Looks at Shakespeare, which won a prize from the Folger Library and was published under the title The Shakespearean Ciphers Examined. The book demonstrated flaws in Gallup's work and in that of others who sought hidden ciphers in Shakespeare's work.

At NSA's request Friedman prepared Six Lectures Concerning Cryptography and Cryptanalysis, which he delivered at NSA. But later the Agency, concerned about security, confiscated the reference materials from Friedman's home.

Death and legacy

thumb|Declassified copy of confiscated 1965 "Friedman Lectures on Cryptology"|alt=

Friedman's health began to fail in the late 1960s, and he died in 1969. Friedman and his wife Elizebeth are buried in Arlington National Cemetery.

Friedman and his wife donated their archives to the library of the George C. Marshall Foundation, which also has had material reclassified and removed by the NSA.

Friedman has been inducted into the Military Intelligence Hall of Fame and there is a building named after William and Elizebeth at the NSA complex at Fort Meade in Maryland. He was also presented the Medal for Merit by President Harry Truman, and the National Security Medal by Dwight Eisenhower.

Friedman has the distinction of having one of the longest known suppressed patent applications, for , a patent for a "cryptographic system". It was filed on July 25, 1933, issued on August 1, 2000.

Friedman Hall, located on Fort Huachuca, Arizona, is named in his honor.

Children

Friedman had two children with his wife, Elizebeth: Barbara Friedman (later Atchison), and John Ramsay Friedman.

Commander Schoen, a character appearing in Neal Stephenson's novel Cryptonomicon, is to a large extent inspired by Friedman. Schoen shares a significant background and personality traits with Friedman, including being one of the top cryptanalysts of the U.S. Army, breaking Japanese codes prior to Japan's involvement in World War II, and the psychological problems that he suffered from as a result. In his acknowledgements, Stephenson writes "Among all these great wartime hackers, some kind of special recognition must go to William Friedman, who sacrificed his health to break the Japanese machine cipher called Purple before the war even began."

Awards and honors

  • 1944: Commendation for Exceptional Civilian Service