Editing Signals intelligence (section)

{{short description|Intelligence-gathering by interception of signals}}
{{Redirect|Sigint}}
{{Use dmy dates|date=January 2023}}
{{More citations needed|date=June 2024}}
{{Intelligence}}[[File:Menwith-hill-radomes.jpg|thumb|[[RAF Menwith Hill]], a large site in the [[United Kingdom]], part of [[ECHELON]] and the [[UKUSA Agreement]] in 2005]]
[[File:Bletchley Park last German intercept.JPG|thumb|A German message intercepted by the British during [[World War II]], signaling Germany's unconditional surrender]]
'''Signals intelligence''' ('''SIGINT''') is the act and field of [[list of intelligence gathering disciplines|intelligence-gathering]] by interception of ''[[signal]]s'', whether [[communication]]s between people ('''communications intelligence'''—abbreviated to '''COMINT''') or from electronic signals not directly used in communication ('''electronic intelligence'''—abbreviated to '''ELINT''').<ref>{{Cite web |title=Signals Intelligence (SIGINT) Overview |url=https://www.nsa.gov/Signals-Intelligence/Overview/ |access-date=2022-12-03 |website=nsa.gov |at=HOME > SIGNALS INTELLIGENCE > OVERVIEW |quote=National Security Agency/Central Security Service > Signals Intelligence > Overview}}</ref> As [[classified information|classified]] and [[sensitive information]] is usually [[encryption|encrypted]], signals intelligence may necessarily involve [[cryptanalysis]] (to decipher the messages). [[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.{{Citation needed|date=October 2019}}