Signals intelligence (SIGINT) is the act and field of intelligence-gathering by interception of signals, whether communications between people or from electronic signals not directly used in communication. As classified and sensitive information is usually encrypted, signals intelligence may necessarily involve cryptanalysis. Traffic analysis—the study of who is signaling to whom and in what quantity—is also used to integrate information, and it may complement cryptanalysis.
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. Initiated when the Soviet Union was an ally of the US, the program continued during the Cold War, when the Soviet Union was considered an enemy.
William Frederick Friedman 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.
Arlington Hall is a historic building in Arlington, Virginia, originally a girls' school and later the headquarters of the United States Army's Signal Intelligence Service (SIS) cryptography effort during World War II. The site presently houses the George P. Shultz National Foreign Affairs Training Center, and the Army National Guard's Herbert R. Temple Jr. Readiness Center. It is located on Arlington Boulevard between S. Glebe Road and S. George Mason Drive.
The Central Security Service (CSS) is a combat support agency of the United States Department of Defense which was established in 1972 to integrate the National Security Agency (NSA) and the Service Cryptologic Components (SCC) of the United States Armed Forces in the field of signals intelligence, cryptology, and information assurance at the tactical level. In 2002, the CSS had approximately 25,000 uniformed members. It is part of the United States Intelligence Community.
Cryptography was used extensively during World War II because of the importance of radio communication and the ease of radio interception. The nations involved fielded a plethora of code and cipher systems, many of the latter using rotor machines. As a result, the theoretical and practical aspects of cryptanalysis, or codebreaking, were much advanced.
The Black Chamber, officially the Cable and Telegraph Section and also known as the Cipher Bureau, was the first peacetime cryptanalytic organization in the United States, operating from 1917 to 1929. It was a forerunner of the National Security Agency (NSA).
OP-20-G or "Office of Chief Of Naval Operations (OPNAV), 20th Division of the Office of Naval Communications, G Section / Communications Security", was the U.S. Navy's signals intelligence and cryptanalysis group during World War II. Its mission was to intercept, decrypt, and analyze naval communications from Japanese, German, and Italian navies. In addition OP-20-G also copied diplomatic messages of many foreign governments. The majority of the section's effort was directed towards Japan and included breaking the early Japanese "Blue" book fleet code. This was made possible by intercept and High Frequency Direction Finder (HFDF) sites in the Pacific, Atlantic, and continental U.S., as well as a Japanese telegraphic code school for radio operators in Washington, D.C.
William Weisband, Sr. was a Ukrainian-American cryptanalyst and NKVD agent, best known for his role in revealing U.S. decryptions of Soviet diplomatic and intelligence codes to Soviet intelligence.
A radio listening station is a facility used for military reconnaissance, especially telecommunications reconnaissance by "intercepting" radio transmitter communications. In contrast to the original eavesdropping on an acoustic speech conversation, radio eavesdropping stations are used to eavesdrop on the information transmitted wirelessly using radio technology. For this purpose, highly sensitive radio receivers and suitable receiving antennas are used.
Project SHAMROCK was the sister project to Project MINARET, an espionage exercise started in August 1945. Project MINARET involved the accumulation of all telegraphic data that entered or exited the United States. The Armed Forces Security Agency (AFSA) and its successor, the National Security Agency (NSA), were given direct access to daily microfilm copies of all incoming, outgoing, and transiting telegrams via the Western Union and its associates RCA and ITT. NSA did the operational interception, and, if there was information that would be of interest to other intelligence agencies, the material was passed to them. Intercepted messages were disseminated to the FBI, CIA, Secret Service, Bureau of Narcotics and Dangerous Drugs (BNDD), and the Department of Defense. No court authorized the operation and there were no warrants.
Before the development of radar and other electronics techniques, signals intelligence (SIGINT) and communications intelligence (COMINT) were essentially synonymous. Sir Francis Walsingham ran a postal interception bureau with some cryptanalytic capability during the reign of Elizabeth I, but the technology was only slightly less advanced than men with shotguns, during World War I, who jammed pigeon post communications and intercepted the messages carried.
Vint Hill Farms Station (VHFS) was a United States Army and National Security Agency (NSA) signals intelligence and electronic warfare facility located in Fauquier County, Virginia, near Warrenton. VHFS was closed in 1997 and the land was sold off in 1999. Today the site hosts various engineering and technology companies, as well as two Federal Aviation Administration (FAA) air traffic control facilities.
The Government of the United Kingdom maintains several intelligence agencies that deal with secret intelligence. These agencies are responsible for collecting, analysing and exploiting foreign and domestic intelligence, providing military intelligence, and performing espionage and counter-espionage. Their intelligence assessments contribute to the conduct of the foreign relations of the United Kingdom, maintaining the national security of the United Kingdom, military planning, public safety, and law enforcement in the United Kingdom. The four main agencies are the Secret Intelligence Service, the Security Service (MI5), the Government Communications Headquarters (GCHQ) and Defence Intelligence (DI). The agencies are organised under three government departments, the Foreign Office, the Home Office and the Ministry of Defence.
Genevieve Marie Grotjan Feinstein was an American mathematician and cryptanalyst. She worked for the Signals Intelligence Service throughout World War II, during which time she played an important role in deciphering the Japanese cryptography machine Purple, and later worked on the Cold War-era Venona project.
William Coffee (1917–1989) was an American cryptographer. He received the Commendation for Meritorious Civilian Service in April 1946 for his role in recruiting and leading a group of African-American cryptographers in the United States Army's Signals Intelligence Service. He began his career in public service with the Civilian Conservation Corps from 1937 to 1940. Soon after, he began working for the Signal Intelligence Service, later known as the Signal Security Agency. Despite being hired as a janitor, he was promoted to a messenger. Upon being promoted, he was assigned the task of hiring a group of black cryptologists at Arlington Hall Station. His success in composing and directing this group elevated him to a status previously unreached by black cryptologists. After the Second World War, Coffee joined the Armed Forces Security Agency, which later became the National Security Agency. Coffee retired from the NSA in 1972. He was inducted into the National Security Agency's Cryptologic Hall of Honor in 2011.
William Lutwiniak was an American crossword constructor who was also known for his work as a cryptologist with the National Security Agency. He composed a total of 8,413 puzzles; his first five thousand were composed between 1965 and 1985, as a hobby.
Gene Grabeel was an American mathematician and cryptanalyst who founded the Venona project.
Japanese army and diplomatic codes. This article is on Japanese army and diplomatic ciphers and codes used up to and during World War II, to supplement the article on Japanese naval codes. The diplomatic codes were significant militarily, particularly those from diplomats in Germany.
Wilma Zimmerman Davis was an early American codebreaker during World War II. She was a leading national cryptanalyst before and during World War II and the Vietnam War. She graduated with a degree in Mathematics from Bethany College and successfully completed navy correspondence course in cryptology. She began her career as a leading cryptanalyst which spanned over 30 years in the United States Army Signal Intelligence Service (SIS), a predecessor of the National Security Agency (NSA) in the 1930s. She was hired by William Friedman, who was a US cryptographer in the Army and led the research division of the Army’s Signal Intelligence in the 1930s. Wilma Davis worked as a cryptanalyst on the Italian, Japanese, Chinese, Vietnamese, and Russian problems. She also worked on the Venona project.
