Venona project

The Venona project was a United States counterintelligence program initiated during World War II by the United States Army's Signal Intelligence Service and later absorbed by the National Security Agency (NSA), that ran from February 1, 1943, until October 1, 1980. It was intended to decrypt messages transmitted by the intelligence agencies of the Soviet Union (e.g. the NKVD, the KGB, and the GRU). During the 37-year duration of the Venona project, the Signal Intelligence Service decrypted and translated approximately 3,000 messages. The signals intelligence yield included discovery of the Cambridge Five espionage ring in the United Kingdom, and also of Soviet espionage of the Manhattan Project in the US, known as Project Enormous. Some of the espionage was undertaken to support the Soviet atomic bomb project. The Venona project remained secret for more than 15 years after it concluded.

Background During World War II and the early years of the Cold War, the Venona project was a source of information on Soviet intelligence-gathering directed at the Western military powers. Although unknown to the public, and even to Presidents Franklin D. Roosevelt and Harry S. Truman, these programs were of importance concerning crucial events of the early Cold War. These included the Julius and Ethel Rosenberg spying case (which was based on events during World War II) and the defections of Donald Maclean and Guy Burgess to the Soviet Union. Most decipherable messages were transmitted and intercepted between 1942 and 1945, during World War II, when the Soviet Union was an ally of the US. Sometime in 1945, the existence of the Venona program was revealed to the Soviet Union by cryptologist-analyst Bill Weisband, an NKVD agent in the US Army's SIGINT. These messages were slowly and gradually decrypted beginning in 1946. This effort continued (many times at a low level of effort in the latter years) through 1980, when the Venona program was terminated. The analyst effort assigned to it was moved to more important projects. To what extent the various individuals referred to in the messages were involved with Soviet intelligence is a topic of minor historical dispute. Most academics and historians have established that most of the individuals mentioned in the Venona decrypts were probably either clandestine assets and/or contacts of Soviet intelligence agents, and very few argue that many of those people probably had no malicious intentions and committed no crimes.

Commencement

The VENONA Project was initiated on February 1, 1943, by Gene Grabeel, an American mathematician and cryptanalyst, under orders from Colonel Carter W. Clarke, Chief of Special Branch of the Military Intelligence Service at that time. Clarke distrusted Joseph Stalin, and feared that the Soviet Union would sign a separate peace with Nazi Germany, allowing Germany to focus its military forces against the United Kingdom and the United States. Cryptanalysts of the US Army's Signal Intelligence Service at Arlington Hall analyzed encrypted high-level Soviet diplomatic intelligence messages intercepted in large volumes during and immediately after World War II by American, British, and Australian listening posts. Frank Rowlett was one of the project leaders.

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. Despite this, the reuse was detected by cryptanalysts in the US.

Breakthrough

The Soviet systems in general used a code to convert words and letters into numbers, to which additive keys (from one-time pads) were added, encrypting the content. When used correctly one-time pad encryption is unbreakable. 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 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, 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 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.

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