The Ministry for State Security (German: Ministerium für Staatssicherheit, pronounced [minɪsˈteːʁiʊm fyːɐ̯ ˈʃtaːtsˌzɪçɐhaɪ̯t]; abbreviated MfS), commonly known as the Stasi (pronounced [ˈʃtaːziː] , an abbreviation of Staatssicherheit), was the state security service and secret police of East Germany from 1950 to 1990. It was one of the most repressive police organisations in the world, infiltrating almost every aspect of life in East Germany, using torture, intimidation and a vast network of informants to crush dissent.
https://en.wikipedia.org/wiki/Stasi