SIGINT stands for SIGnals INTelligence, which is intelligence-gathering by interception of signals, whether by radio interception or other means. Intelligence Gathering Disciplines HUMINT - Human Intelligence - gathered from a person on the ground IMINT - Imagery Intelligence - gathered from satellite and aerial photography MASINT - Measurement and Signature Intelligence ACOUSTINT - Acoustic Intelligence - gathered from acoustical sources CBINT - Chemical and Biological Intelligence - gathered from chemical and biological weapons and hazards DEWINT - Directed Energy...

SIGINT

SIGINT is actually a broad discipline in which multiple sub-disciplines fall under. There are three major sub-disciples that fall under SIGINT which are COMmunications INTelligence (COMINT), ELectronic INTelligence (ELINT), and Foreign Instrumentation Signals INTelligence (FISINT). It should be noted that COMINT is commonly referred to as SIGINT, which can cause confusion when talking about the broader intelligence disciplines. ELINT stands for ELectronic INTelligence, and refers to intelligence-gathering by use of electronic sensors. ...

SIGINT became far more central to military (and to some extent diplomatic) intelligence generally with the mechanization of armies, development of blitzkrieg tactics, use of submarine and commerce raiders warfare, and the development of practicable radio communications. For example, failure to properly protect its communications fatally compromised the Russian Army in its advance early in WWI and led to the disastrous defeat by the Germans under Ludendorff and Hindenburg at the Battle of Tannenberg. Similarly, the interception and decryption of the Zimmerman telegram was an important factor in the US decision to enter the War. Blitzkrieg relied on close cooperation between infantry and panzers (tanks). ... USS Los Angeles A submarine is a specialized watercraft that can operate underwater. ... Radio transmition diagram and electromagnetic waves For other uses see: radio (disambiguation) Radio is a technology that allows the transmission of signals by modulation of electromagnetic waves with frequencies below those of light. ... General Erich Ludendorff Erich Ludendorff (sometimes given incorrectly as Erich von Ludendorff) (April 9, 1865 – December 20, 1937, Tutzing, Bavaria, Germany) was a German Army officer, noted as a general during World War I. Ludendorff was born in Kruszewnia near Posen, Prussia (now Poznań, Poland). ... Paul von Hindenburg President of Germany Paul von Hindenburg (full name Paul Ludwig Hans Anton von Beneckendorff und von Hindenburg) (October 2, 1847 – August 2, 1934) was a German Field Marshal and statesman. ... The Battle of Tannenberg of 1914 was a decisive conflict between Russia and Germany in the first days of World War I. The Russian 1st and 2nd Armies and the German Eighth Army fought from August 17 to September 2, 1914. ... The Zimmermann Telegram was a telegram dispatched by the Foreign Secretary of the German Empire, Arthur Zimmermann, on January 16, 1917, to the German ambassador in Mexico, Heinrich von Eckardt, at the height of World War I. It instructed the ambassador to approach the Mexican government with a proposal to...

On the negative side, the inability of British commanders to take seriously traffic analysis information from intercepts was instrumental in the failure to achieve more than they did at the Battle of Jutland, thus losing what might have been a major opportunity. Traffic analysis is the process of intercepting and examining messages in order to deduce information from patterns in communication. ... The Battle of Jutland, known in Germany as the Battle of the Skagerrak (Skagerrakschlacht), was the largest naval battle of World War I, and the only full-scale clash of battleships in that war. ...

The use of SIGINT had important implications during WWII as well. Early on, Admiralty dismissal of SIGINT information (also traffic analysis in this instance) contributed to the loss of HMS Glorious in 1940. The Allied ability to intercept and decrypt the German Enigma (Ultra) and Japanese Purple (Magic) traffic proved to be a great military advantage. Perhaps most dramatically, intercepts of Japanese naval communications yielded information that gave Admiral Nimitz the upper hand in the ambush that resulted in the Japanese Navy's defeat at the Battle of Midway, six months after the Pearl Harbor disaster. HMS Glorious was a warship of the Royal Navy. ... 1940 was a leap year starting on Monday (link will take you to calendar). ... In the history of cryptography, the Enigma was a portable cipher machine used to encrypt and decrypt secret messages. ... Ultra (sometimes capitalised ULTRA) was the name used by the British for intelligence resulting from decryption of German communications in World War II. The term eventually became the standard designation in both Britain and the United States for all intelligence from high-level cryptanalytic sources. ... A fragment of an actual Purple machine found in Berlin at the end of WWII In the history of cryptography, 97-shiki-obun In-ji-ki (九七式欧文印字機) (System 97 Printing Machine for European Characters) or Angooki Taipu B (暗号機B型) (Type B Cipher Machine), codenamed PURPLE by the United States, was... In World War II, Magic was the US codename for intelligence derived from the cryptanalysis of Purple, a Japanese foreign office cipher. ... Chester Nimitz Chester William Nimitz (February 24, 1885 – February 20, 1966) was the Commander in Chief of Pacific Forces for the United States and Allied forces during World War II. He was the nations leading authority on submarines, as well as Chief of the Navy Bureau of Navigation in... The Battle of Midway, fought in World War II, took place on June 5, 1942 (June 4–June 7 in U.S. time zones). ... The Imperial Japanese Navy made its attack on Pearl Harbor on the morning of December 7, 1941. ...

As sensitive information is often encrypted, SIGINT often involves the use of cryptanalysis. However, traffic analysis can produce information, often valuable information, even when the messages themselves cannot be decrypted. For the Game Boy Advance cheat device, see CodeBreaker (Game Boy) Cryptanalysis (from the Greek kryptós, hidden, and analýein, to loosen or to untie) is the study of methods for obtaining the meaning of encrypted information without access to the secret information which is normally required to do...

Intelligence derived from any of the SIGINT disciplines are very sensitive due to the ability to determine the source of the information. By determining the source of the intelligence information, the enemy can deny access or even send deceptive information to confuse and otherwise reduce the trustworthiness of the information.

Past and present SIGINT activities

• Ultra
• Magic (cryptography)
• Purple code
• ECHELON

Ultra (sometimes capitalised ULTRA) was the name used by the British for intelligence resulting from decryption of German communications in World War II. The term eventually became the standard designation in both Britain and the United States for all intelligence from high-level cryptanalytic sources. ... In World War II, Magic was the US codename for intelligence derived from the cryptanalysis of Purple, a Japanese foreign office cipher. ... A fragment of an actual Purple machine found in Berlin at the end of WWII In the history of cryptography, 97-shiki-obun In-ji-ki (九七式欧文印字機) (System 97 Printing Machine for European Characters) or Angooki Taipu B (暗号機B型) (Type B Cipher Machine), codenamed PURPLE by the United States, was... Antenna 4 (through the wire) in former Echelon intelligence gathering station at Silvermine, Cape Peninsula, South Africa. ...

Further reading

• Nigel West, The SIGINT Secrets: The Signals Intelligence War, 1900 to Today (William Morrow, New York, 1988)

See also

• HUMINT: Human intelligence
• COMINT: Communications intelligence
• ELINT: Electronic intelligence
• IMINT: Imagery intelligence
• RAF Intelligence: Royal Air Force Intelligence Branch

HUMINT, short for human intelligence, is an intelligence gathering discipline collecting information either by interviewing or tracking a subject of investigation, or by using a combination of black techniques to gain confessions or involuntary disclosure of information. ... ELINT stands for ELectronic INTelligence, and refers to intelligence-gathering by use of electronic sensors. ... IMINT, short for IMagery INTelligence, is an intelligence gathering discipline which collects information via satellite and aerial photography. ... The Royal Air Force has its own dedicated intelligence branch. ... The Royal Air Force (often abbreviated to RAF) is the air force branch of the UK Armed Forces. ...

External links

• SIGINT News Group - Discussion Forum