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THE VENONA INTERCEPTS (Washington, D.C., 1946-1980)
Events
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Postscript -- The Nuclear Age, 1945-Present
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Informing the Public, August 1945
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The Manhattan Engineer District, 1945-1946
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First Steps toward International Control,
1944-1945
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Search for a Policy on International Control,
1945
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Negotiating International Control,
1945-1946
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Civilian Control of Atomic Energy,
1945-1946
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Operation Crossroads, July 1946
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The VENONA Intercepts, 1946-1980
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The Cold War, 1945-1990
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Nuclear Proliferation, 1949-present
Soviet intelligence officers in the United States
regularly communicated with their superiors in Moscow via
telegraphic cables. These messages were encrypted of
course, but in 1946 the United States, with the assistance
of Great Britain, began to decrypt a good number of these
messages. This program led to the eventual capture
of several
Soviet spies within the Manhattan Project. The VENONA intercepts, as they were codenamed,
remained a closely-guarded secret, known only to a handful
of government officials, until the program was
declassified in 1995.
The cables should have been impossible to decrypt.
Collecting them was easy. The United States
government simply acquired copies of all cables openly
sent to and from various Soviet embassies and
consulates. These messages were encrypted by a means
known as a "one-time pad." This meant
that, at least in theory, decrypting them should have been
impossible. The Army's Signal Intelligence Service
began working on the problem in 1943, and they gradually
discovered a Soviet procedural error that allowed many of
the messages to be painstakingly decrypted. Portions
of messages began to become clear in 1946, and by 1948
numerous messages were being recovered by the team led by
Meredith Gardner (above left). In 1948,
the Federal Bureau of Investigation (FBI) was also
brought into the investigation, its efforts led by Robert
Lamphere (right). Although only messages up to 1945 were
vulnerable to decryption, and these messages were several
years old by that point, they still contained references
to spies who had never been detected, including many who
presumably continued to work for Soviet
intelligence. From 1948 to 1951, numerous Soviet
spies were uncovered and prosecuted this way, including
the atomic spies Klaus Fuchs (below),
David Greenglass, Greenglass's handler Julius Rosenberg,
and Rosenberg's wife Ethel. Other sources, such as
Theodore Hall, were detected, but without sufficient
corroborating evidence other than VENONA, the government
was unable to prosecute them. (The VENONA secret was
considered too valuable to reveal as evidence in an open
court proceeding.)
Once messages were decrypted and translated into English,
however, the identity of the individuals mentioned in them
was still often not apparent. Soviet intelligence
assigned every person a unique codename and sometimes
changed it. (For example, Julius Rosenberg was
ANTENNA, later changed to LIBERAL, and Theodore Hall was
MLAD.) Nonetheless, it was often possible to
determine who each codename referred to based on clues
within the messages. Sometimes the message where the
individual is first given a codename happens to be one of
those decrypted, in which case the individual's identity
is known with certainty. In other cases, rather
obvious clues make identification simple, such as when the
name of ANTENNA's wife was openly given as
"Ethel." Most people were identified
through follow-up investigation by the FBI based on the
descriptions of their work, their lives, their appearance,
and even their codename itself. (MLAD means
"youngster" in Russian; Hall was only 19 when he
began his work as a spy.) In some cases, especially
when dealing with sources who were
only mentioned in a handful of decrypted messages, a
Soviet spy's identity remains unknown to this
day.
Additional wartime messages continued to be decrypted
during the 1950s and beyond, but the "value
added" of these decryptions gradually lessened over
time. Soviet intelligence learned of the VENONA
program in 1949 through its highly-placed British agent,
Kim Philby, but there was nothing they could do to stop
it. The program was finally formally terminated on
October 1, 1980.
Rumors of an important codebreaking effort circulated
among journalists and historians throughout the 1980s and
the early 1990s, but there was no formal confirmation of
the existence of VENONA until it was declassified in 1995.
Today anyone who is interested can view images of the
actual decrypted cables on the
National Security Agency's
web page at
https://www.nsa.gov/Helpful-Links/NSA-FOIA/Declassification-Transparency-Initiatives/Historical-Releases/Venona/.
-
Informing the Public, August 1945
-
The Manhattan Engineer District, 1945-1946
-
First Steps toward International Control,
1944-1945
-
Search for a Policy on International Control,
1945
-
Negotiating International Control,
1945-1946
-
Civilian Control of Atomic Energy,
1945-1946
-
Operation Crossroads, July 1946
-
The VENONA Intercepts, 1946-1980
-
The Cold War, 1945-1990
-
Nuclear Proliferation, 1949-present
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Sources and notes for this page.
The text for this page is original to the Department of
Energy's
Office of History and Heritage Resources. The information for this entry is drawn
primarily from the National Security Agency's web site
devoted to the history of VENONA, which is available at
https://www.nsa.gov/Helpful-Links/NSA-FOIA/Declassification-Transparency-Initiatives/Historical-Releases/Venona/,
and John Earl Haynes and Harvey Klehr,
Venona: Decoding Soviet Espionage in America
(New Haven and London: Yale University Press, 1999),
especially 1-22. See also Herbert Romerstein and
Eric Breindel,
The Venona Secrets: Exposing Soviet Espionage and
America's Traitors
(Washington: Regnery Publishing, Inc., 2000), and Allen
Weinstein and Alexander Vassiliev,
The Haunted Wood: Soviet Espionage in America -- the
Stalin Era
(New York: Random House, 1999). The
Los Alamos ID Badge photograph of
Klaus Fuchs was taken in 1944; it is
courtesy the
Los Alamos National Laboratory (LANL)
and is reprinted in Rachel Fermi and Esther Samra,
Picturing the Bomb: Photographs from the Secret World
of the Manhattan Project (New York: Harry N. Abrams, Inc., Publishers, 1995),
106. All of the other images on this web page are
courtesy the
National Security Agency.
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