Editing Venona project (section)

==Decryption==
This message traffic, which was encrypted with a [[one-time pad]] system, was stored and analyzed in relative secrecy by hundreds of cryptanalysts over a 40-year period starting in the early 1940s. When used correctly, the one-time pad encryption system, which has been used for all the most-secret military and diplomatic communication since the 1930s, is unbreakable. However, due to a serious blunder on the part of the Soviets, some of this traffic was vulnerable to cryptanalysis. The Soviet company that manufactured the one-time pads produced around 35,000 pages of duplicate key numbers, as a result of pressures brought about by the German advance on Moscow during World War II. The duplication—which undermines the security of a one-time system—was discovered, and attempts to lessen its impact were made by sending the duplicates to widely separated users.<ref>[http://www.nsa.gov/public_info/_files/crypto_almanac_50th/venona_an_overview.pdf Cryptologic Almanac 50th Anniversary Series – VENONA: An Overview (DOCID: 3575728)] {{webarchive|url=https://web.archive.org/web/20160304100650/https://www.nsa.gov/public_info/_files/crypto_almanac_50th/VENONA_An_Overview.pdf |date=2016-03-04}}. Released by NSA on 06-12-2009, FOIA Case # 52567.</ref> Despite this, the reuse was detected by cryptanalysts in the US.

===Breakthrough===
[[File:Genevieve Grotjan Feinstein.jpg|thumb|[[Genevieve Feinstein]]<ref>{{cite web|url=http://www.nsa.gov/about/cryptologic_heritage/women/honorees/feinstein.shtml |title=Women in Cryptologic History – Genevieve Feinstein – NSA/CSS |publisher=Nsa.gov |date=2009-01-15 |access-date=2014-02-15}}</ref>]]
The Soviet systems in general used a [[code]] to convert words and letters into numbers, to which additive [[key (cryptography)|key]]s (from one-time pads) were added, encrypting the content. When used correctly so that the [[plaintext]] is of a length equal to or less than that of a random key, one-time pad encryption is unbreakable.<ref>{{cite web |url=http://www.world.std.com/~franl/crypto/one-time-pad.html |archive-url=https://web.archive.org/web/20080516225512/http://www.world.std.com/~franl/crypto/one-time-pad.html |archive-date=2008-05-16 |title=Why Are One-Time Pads Perfectly Secure? |author=Francis Litterio}}</ref> However, cryptanalysis by American code-breakers revealed that some of the one-time pad material had incorrectly been reused by the Soviets (specifically, entire pages, although not complete books), which allowed decryption (sometimes only partial) of a small part of the traffic.

Generating the one-time pads was a slow and labor-intensive process, and the outbreak of war with Germany in June 1941 caused a sudden increase in the need for coded messages. It is probable that the Soviet code generators started duplicating cipher pages in order to keep up with demand.

It was Arlington Hall's Lieutenant [[Richard Hallock (Venona Project)|Richard Hallock]], working on Soviet "Trade" traffic (so called because these messages dealt with Soviet trade issues), who first discovered that the Soviets were reusing pages. Hallock and his colleagues, amongst whom were [[Genevieve Feinstein]], [[Cecil Phillips]], [[Frank W. Lewis|Frank Lewis]], [[Frank Wanat]], and [[Lucille Campbell]], went on to break into a significant amount of Trade traffic, recovering many one-time pad additive key tables in the process.
[[File:Meredith Gardner, at far left, working with cryptanalysts.jpg|thumb|[[Meredith Gardner]] (far left); most of the other code breakers were young women.]] <!-- yes, Meredith's a man -->
A young [[Meredith Gardner]] then used this material to break into what turned out to be NKVD (and later [[GRU (Soviet Union)|GRU]]) traffic by reconstructing the code used to convert text to numbers. Gardner credits [[Marie Meyer (linguist)|Marie Meyer]], a linguist with the [[Signal Intelligence Service]] with making some of the initial recoveries of the Venona codebook.<ref>{{Cite web|url=https://www.nsa.gov/About-Us/Current-Leadership/Article-View/Article/1620935/marie-meyer/|title=Marie Meyer > National Security Agency {{!}} Central Security Service > Article View|website=www.nsa.gov|access-date=2019-11-21}}</ref> [[Samuel P. Chew|Samuel Chew]] and Cecil Phillips also made valuable contributions. On December 20, 1946, Gardner made the first break into the code, revealing the existence of Soviet espionage in the [[Manhattan Project]].<ref>
{{cite web
| author = Daniel Patrick Moynihan
| author-link = Daniel Patrick Moynihan
| year = 1997
| url = https://fas.org/sgp/library/moynihan/appa6.html
| title = Report of the Commission On Protecting And Reducing Government Secrecy; Appendix A: The Experience of The Bomb
| publisher = United States Government Printing Office
| access-date = 2006-06-18
}}</ref> Venona messages also indicated that Soviet spies worked in Washington in the [[United States Department of State|State Department]], [[United States Department of the Treasury|Treasury]], [[Office of Strategic Services]] (OSS), and even the [[White House]]. Very slowly, using assorted techniques ranging from [[traffic analysis]] to [[defector]] information, more of the messages were decrypted.

Claims have been made that information from the physical recovery of code books (a partially burned one was obtained by the Finns) to [[Covert listening device|bugging]] embassy rooms in which text was entered into encrypting devices (analyzing the keystrokes by listening to them being punched in) contributed to recovering much of the plaintext. These latter claims are less than fully supported in the open literature.

One significant aid (mentioned by the NSA) in the early stages may have been work done in cooperation between the [[Japan]]ese and [[Finland|Finnish]] cryptanalysis organizations; when the Americans broke into Japanese codes during World War II, they gained access to this information.<ref>{{Cite book |last=Mundy |first=Liza |title=Code girls: the untold story of the American women code breakers of World War II |publisher=Hachette Books |year=2017 |isbn=978-0-316-35253-6 |edition=1st |location=Boston |page=38}}</ref> There are also reports that copies of signals purloined from Soviet offices by the [[Federal Bureau of Investigation]] (FBI) were helpful in the cryptanalysis. The Finnish radio intelligence sold much of its material concerning Soviet codes to the OSS in 1944 during [[Operation Stella Polaris]], including the partially burned code book.<ref>{{ cite book
| last = West
| first = Nigel
| title = Venona: the greatest secret of the Cold War
| publisher = HarperCollins
| year = 2000
| location = London
| pages = 3–10
| isbn = 978-0-00-653071-8
}}</ref>

===Results===
The NSA reported that (according to the serial numbers of the Venona cables) thousands of cables were sent, but only a fraction were available to the cryptanalysts. Approximately 2,200 messages were decrypted and translated; about half of the 1943 GRU-Naval Washington to Moscow messages were broken, but none for any other year, although several thousand were sent between 1941 and 1945. The decryption rate of the NKVD cables was as follows:
* 1942: 1.8%
* 1943: 15.0%
* 1944: 49.0%
* 1945: 1.5%

Out of some hundreds of thousands of intercepted encrypted texts, it is claimed under 3,000 have been partially or wholly decrypted. All the duplicate one-time pad pages were produced in 1942, and almost all of them had been used by the end of 1945, with a few being used as late as 1948. After this, Soviet message traffic reverted to being completely unreadable.<ref>
{{cite book
|author1=Haynes, John Earl |author2=Klehr, Harvey
|name-list-style=amp |year = 2000
| title = Venona: Decoding Soviet Espionage in America
| publisher = Yale University Press
| page = 55
| isbn = 978-0-300-08462-7
}}</ref>

The existence of Venona decryption became known to the Soviets within a few years of the first breaks.<ref name="osti.gov">{{Cite web |title=Manhattan Project: The Venona Intercepts |url=https://www.osti.gov/opennet/manhattan-project-history/Events/1945-present/venona.htm |access-date=2023-10-10 |website=www.osti.gov}}</ref> It is not clear whether the Soviets knew how much of the message traffic or which messages had been successfully decrypted. At least one Soviet penetration agent, British [[Secret Intelligence Service]] representative to the US [[Kim Philby]], was told about the project in 1949, as part of his job as liaison between British and US intelligence.<ref name="osti.gov"/> Since all of the duplicate one-time pad pages had been used by this time, the Soviets apparently did not make any changes to their cryptographic procedures after they learned of Venona. However, this information allowed them to alert those of their agents who might be at risk of exposure due to the decryption.

===Significance===
The decrypted messages gave important insights into Soviet behavior in the period during which duplicate one-time pads were used. With the first break into the code, Venona revealed the existence of Soviet espionage<ref>
{{cite book
| last = Moynihan
| first = Daniel Patrick
| year = 1998
| title = Secrecy: The American Experience
| url = https://archive.org/details/secrecyamericane00moyn
| url-access = registration
| publisher = Yale University Press
| page = [https://archive.org/details/secrecyamericane00moyn/page/54 54]
| isbn = 978-0-300-08079-7
}} "these intercepts provided ... descriptions of the activities of precisely the same Soviet spies who were named by defecting Soviet agents [[Aleksandr Mikhailovich Orlov|Alexander Orlov]], [[Walter Krivitsky]], [[Whittaker Chambers]] and [[Elizabeth Bentley]]."</ref> at the [[Los Alamos National Laboratory#The Manhattan Project|Manhattan Project's Site Y (Los Alamos)]].<ref>
{{cite web
 |url          = http://www.access.gpo.gov/congress/commissions/secrecy/pdf/12hist1.pdf
 |title        = A Brief Account of the American Experience
 |author       = Commission on Protecting and Reducing Government Secrecy
 |work         = Report of the Commission on Protecting and Reducing Government Secrecy. VI; Appendix A
 |publisher    = US Government Printing Office
 |pages        = A–27
 |access-date   = 2006-06-26
 |archive-url  = https://web.archive.org/web/20110514040131/http://www.access.gpo.gov/congress/commissions/secrecy/pdf/12hist1.pdf
 |archive-date = 2011-05-14
 
}} "Thanks to successful espionage, the Russians tested their first atom bomb in August 1949, just four years after the first American test. As will be discussed, we had learned of the Los Alamos spies in December 1946—December 20, to be precise. The US Army Security Agency, in the person of Meredith Knox Gardner, a genius in his own right, had broken one of what it termed the Venona messages—the transmissions that Soviet agents in the United States sent to and received from Moscow."</ref> Identities soon emerged of American, Canadian, Australian, and British spies in service to the Soviet government, including [[Klaus Fuchs]], [[Alan Nunn May]], and Donald Maclean. Others worked in Washington in the [[State Department]], the Treasury, OSS,<ref>
{{cite web
 |url          = http://www.access.gpo.gov/congress/commissions/secrecy/pdf/12hist1.pdf
 |title        = A Brief Account of the American Experience
 |author       = Commission on Protecting and Reducing Government Secrecy
 |work         = Report of the Commission on Protecting and Reducing Government Secrecy. VI; Appendix A
 |publisher    = US Government Printing Office
 |pages        = A–7
 |access-date   = 2006-06-26
 |archive-url  = https://web.archive.org/web/20110514040131/http://www.access.gpo.gov/congress/commissions/secrecy/pdf/12hist1.pdf
 |archive-date = 2011-05-14
 
}} "KGB cables indicated that the Office of Strategic Services (OSS) in World War II had been thoroughly infiltrated with Soviet agents."</ref> and even the White House.

The messages show that the US and other nations were targeted in major espionage campaigns by the Soviet Union as early as 1942. Among those identified are [[Julius and Ethel Rosenberg]], [[Alger Hiss]], [[Harry Dexter White]] (the second-highest official in the Treasury Department), [[Lauchlin Currie]]<ref>{{cite web
| url = http://www.nsa.gov/about/_files/cryptologic_heritage/publications/wwii/eavesdropping.pdf
| title = Eavesdropping on Hell
| publisher = National Security Agency
| access-date = 2006-06-26
| archive-date = November 8, 2017
| archive-url = https://web.archive.org/web/20171108151305/https://www.nsa.gov/about/_files/cryptologic_heritage/publications/wwii/eavesdropping.pdf
| url-status = dead
}} "Currie, known as PAZh (Page) and White, whose cover names were YuRIST (Jurist) and changed later to LAJER (Lawyer), had been Soviet agents since the 1930s. They had been identified as Soviet agents in Venona translations and by other agents turned witnesses or informants for the FBI and [[United States Department of Justice|Justice Department]]. From the Venona translations, both were known to pass intelligence to their handlers, notably the [[Greg Silvermaster#Silvermaster group|Silvermaster network]]."</ref> (a personal aide to Franklin Roosevelt), and [[Maurice Halperin]]<ref>{{cite web|last=Warner |first=Michael |year=2000 |url=https://www.cia.gov/csi/books/oss/art07.htm |title=The Office of Strategic Services: America's First Intelligence Agency; Chapter: X-2 |publisher=Central Intelligence Agency Publications |access-date=2006-06-27  |archive-url=https://web.archive.org/web/20060629114037/http://www.cia.gov/csi/books/oss/art07.htm |archive-date=June 29, 2006}}</ref> (a section head in the Office of Strategic Services).

The identification of individuals mentioned in Venona transcripts is sometimes problematic, since people with a "covert relationship" with Soviet intelligence are referenced by [[cryptonym]]s.<ref>{{cite book
| last = Moynihan
| first = Daniel Patrick
| year = 1998
| title = Secrecy: The American Experience
| publisher = Yale University Press
| page = [https://archive.org/details/secrecyamericane00moyn/page/54 54]
| isbn = 978-0-300-08079-7
| url = https://archive.org/details/secrecyamericane00moyn/page/54
}}</ref> Further complicating matters is the fact the same person sometimes had different cryptonyms at different times, and the same cryptonym was sometimes reused for different individuals. In some cases, notably Hiss, the matching of a Venona cryptonym to an individual is disputed. In many other cases, a Venona cryptonym has not yet been linked to any person. According to authors [[John Earl Haynes]] and [[Harvey Klehr]], the Venona transcripts identify approximately 349 Americans who they claim had a covert relationship with Soviet intelligence, though fewer than half of these have been matched to real-name identities.<ref>
{{cite book
|author1=Haynes, John Earl |author2=Klehr, Harvey
|name-list-style=amp |year = 2000
| title = Venona: Decoding Soviet Espionage in America
| publisher = Yale University Press
| page = 12
| isbn = 978-0-300-08462-7
}}</ref> However, not every agent may have been communicating directly with Soviet intelligence. Each of those 349 persons may have had many others working for, and reporting only to, them.

The OSS, the predecessor to the [[Central Intelligence Agency]] (CIA), housed at one time or another between fifteen and twenty Soviet spies.<ref>
{{cite web
| last = Warner
| first = Michael
| year = 2000
| url = https://www.cia.gov/csi/books/oss/art07.htm
| title = The Office of Strategic Services: America's First Intelligence Agency; Chapter: X-2
| publisher = Central Intelligence Agency Publications
| access-date = 2006-06-26
| archive-url = https://web.archive.org/web/20070510011705/https://www.cia.gov/csi/books/oss/art07.htm
| archive-date = 2007-05-10 <!-- new URL: https://www.cia.gov/library/center-for-the-study-of-intelligence/csi-publications/books-and-monographs/oss/art07.htm -->
}}</ref> [[Duncan Lee]], [[Donald Niven Wheeler|Donald Wheeler]], [[Jane Foster Zlatowski]], and Maurice Halperin passed information to Moscow. The [[War Production Board]], the [[Board of Economic Warfare]], the [[Office of the Coordinator of Inter-American Affairs]], and the [[Office of War Information]], included at least half a dozen Soviet sources each among their employees.

=== Black Friday === 

In late October 1948 the Soviets began changing their ciphers one by one in rapid succession. They also stopped the use of UHF radio links from Germany and Austria to Moscow, using (overhead) landline instead. While Navy investigators thought it was a routine systems upgrade others were not so sure and later it was attributed to two Soviet spies: American William (Bill) [[Bill Weisband|Weisband]], a linguist at Arlington Hall and British [[Kim Philby]] in the SIS.{{sfn|Vogel|2019|pp=15-17 }} 

At this time some  information was trickling in from US intercepts and rare overflights near the East-West border; but with a dearth in intelligence, not even a hint was received of the North Korean attack (approved by Stalin) on South Korea in June 1950. This led to the approval of [[Operation Gold]] in Berlin, a joint CIA/SIS operation to tap into underground telephone cables a short distance across the border in East Berlin; the scheme was based on [[Operation Silver (1949)|Operation Silver]] a British SIS operation in Vienna.{{sfn|Vogel|2019|pp=}}  

Operation Gold was betrayed to the NKVD/KGB by British SIS member [[George Blake]] even before it started intercepting in May 1955. But to avoid compromising Blake, it was allowed to continue to April 1956, with knowledge of the project kept inside the organisation.{{sfn|Vogel|2019|pp= 227,280 }}