For the article about the POSIX signal, see SIGINT (POSIX).
For the article about the Metal Gear Solid 3:SE Informative, see Sigint (MGS:3).

SIGINT stands for SIGnals INTelligence, which is intelligence-gathering by interception of signals, whether by radio interception or other means.



SIGINT is actually a broad discipline in which multiple sub-disciplines fall under. Two major sub-disciples that fall under SIGINT are ELINT and COMINT. It should be noted that COMINT is commonly refered to as SIGINT, which can cause confusion when talking about the broader intelligence disciplines.

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.

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.

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.

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.

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

Further reading

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

See also

External links

no:Signaletterretning sl:SIGINT


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