SIGINT (signals intelligence) is information gained by the collection and analysis of the electronic signals and communications of a given target.
Intelligence, in this context, is information that provides an organization or individual with support for making decisions and possibly gaining a strategic advantage. The term is often abbreviated as “intel.” Intelligence agencies worldwide use SIGINT in both foreign and domestic data gathering.
Originally SIGINT mostly consisted of communications intelligence (COMINT). SIGINT now has two main fields: COMINT, which is gathered through accessing the communications of individuals, and ELINT (electronic intelligence), which is gathered through the use of electronic sensors. SIGINT has also been extended to encompass information gathered from other types of signal interception and the disruption of these signals. Those activities are not covered by privacy laws. Since the invention of radio, the general consensus has been that radio waves cannot be owned, so interception is legal and as such does not require warrants as wiretap does.
The U.S. intelligence community claims that it only uses SIGINT related to the communications of foreign entities for the purposes of national security. However, documents leaked by Edward Snowden in 2013 and other revelations possibly brought about as a result of the Snowden effect demonstrate that the NSA has used many devices to gather SIGINT of both domestic and foreign targets through a program called Tailored Access Operations (TAO).
- USB sticks secretly fitted with radio transmitters.
- iPhone malware used to monitor the communications and activities of users.
- Portable continuous wave generators that can monitor the keyboard activities of even offline computers through a keyboard vibration attack.
- “LAMPSTAND” devices that can interfere with wireless connections at distances up to eight miles.
The term SIGINT was coined by the United States Department of Defense.