|Dr Solomon Kullback
(1903–1994) was a US cryptanalyst and mathematician.
Kullback was one of the first three employees hired by William F.
Friedman at the US Army's Signal Intelligence Service (SIS) in the
1930s, along with Frank Rowlett and Abraham Sinkov. He went on to a
long and distinguished career at SIS and its eventual successor, the
National Security Agency (NSA). Kullback was the Chief Scientist at
the NSA until his retirement in 1962, whereupon he took a position at
the George Washington University.
The Kullback-Leibler divergence is named after Kullback and Richard
attended Boy's High School in Brooklyn, then City College of New York.
His intention had been to teach, and he returned to Boy's High to do
it, but soon found it not to his taste; he discovered his real
interest was using mathematics, not teaching it.
At the suggestion of Abraham Sinkov, who showed him a Civil Service
flyer for "junior mathematicians" at US$2,000 per year, he took the
examination. Both passed, and were assigned to Washington as junior
Upon arrival in Washington, Kullback was assigned to William F.
Friedman. Friedman had begun an intensive program of training in
cryptology for his new civilian employees. For several summers
running, the SIS cryptanalysts attended training camps at Fort Meade
until they received commissions as reserve officers in the Army.
Kullback and Sinkov took Friedman's admonitions on education seriously
and spent the next several years attending night classes; both
received their doctorates in mathematics. Afterward, Kullback
rediscovered a love of teaching; he began offering evening classes in
mathematics at George Washington University from 1939 on, and found a
new pleasure in teaching.
Once they had completed the training, these three were put to the work
for which they had actually been hired, compilations of cipher or code
material for the U.S. Army. Another task was to test commercial cipher
devices which vendors wished to sell to the U.S. government.
Kullback worked in partnership with Frank Rowlett against RED
messages. Almost overnight, these two unravelled the keying system and
then the machine pattern -- with nothing but the intercepted messages
in hand. Using the talents of linguist John Hurt to translate text,
SIS started issuing current intelligence to military decision-makers.
In May 1942, five months after Pearl Harbor, now-Major Kullback was
sent to Britain to expedite these exchanges. Kullback learned how at
Bletchley Park the British were producing intelligence of high quality
by exploiting the Enigma machine. He also cooperated with the British
in the solution of more conventional German codebook-based systems.
Shortly after his return to the States, Kullback moved into the
Japanese section as its chief.
When the NSA was formed in 1952, Rowlett became chief of
cryptanalysis. The primary problem facing R&D in the post-war period
was development of high-speed processing equipment. Kullback
supervised a staff of about 60, including such innovative thinkers in
ADP development as Leo Rosen and Sam Snyder. His staff pioneered new
forms of input and memory, such as magnetic tape and drum memory, and
compilers to make machines truly "multi-purpose." Kullback gave
priority to using computers to generate COMSEC materials.
Solomon Kullback retired from NSA in 1962, and focused directly on his
teaching at George Washington University. His list of publications on
statistics, already long, grew even more.
COL Kullback is a member of the Military Intelligence Hall of Fame.
Solomon Kullback is remembered by his colleagues at NSA as
straightforward; one described him as "totally guileless, you always
knew where you stood with him." One former NSA senior recalled him as
a man of unlimited energy and enthusiasm and a man whose judgment was
usually "sound and right."
In popular culture
Kullback may be mentioned or play a
major part of the storyline in the upcoming Dan Brown novel, The
Solomon Key, the Solomon part potentially referencing him[citation
needed]. Given the Masonic subject matter implied by Dan Brown, the
person referenced in the book's title may be more likely to be King
It is possible that the character of Lawrence Waterhouse from the
novel Cryptonomicon by Neal Stephenson was partially based on Solomon