The Ministerium für Staatssicherheit ("Ministry of State Security") was the Secret Police / State Sec of East Germany. Their job was to find dissenters and torture them into becoming productive members of the state. From this emerged the most frighteningly effective and efficient secret police in Europe; and, on that note, perhaps the closest any Real Life Secret Police has come to being the Thought Police.
What especially made Stasi infamous was their decision in the 1970s to drop the old totalitarian MO of arresting and torturing dissents after deeming it too ineffective, and instead instigate campaigns of psychological harassment and manipulation of their targets straight out of the playbook of Josef Stalin's terror methods, something which also extended to their interrogation and punishment techniques where "cruder" courses of action, such as beatings and hard labor, were often foregone in favor of more insidious things, such as extremely prolonged solitary confinement or other forms of psychological torture. As an old saying goes "The Gestapo were bone breakers. The Stasi were soul breakers."
The psychological torture employed by the Stasi against political undesirables was a form of gaslighting known as Zersetzung, with the idea that it will eventually cause them to have a mental breakdown and have too little energy to challenge the government. The biggest advantage that Zersetzung gave was that its subtle nature meant that it was able to be plausibly denied.
The Stasi also took mass surveillance to new heights. To give you a baseline, the old KGB "only" had one officer for every 5,830 citizens, and its modern counterpart (the FSB in Putin's Russia) can work about 1 officer for 273 citizens (as the old KGB was spread out over the entire USSR). The best the Gestapo could manage was one officer for 2,000 citizens. The Stasi had one officer for every 166 citizens of East Germany. And these numbers only count official full-time agents—when you include the vast numbers of East Germans who were at one time or another acting as part-time or even full-time informants for the Stasi, the number goes up to one in seven by some estimates. No one was sure if they were being watched or not, and could never tell if their friends or family were informing on them. Often people had no choice. The Stasi even went so far as having informants undergo Marrying the Mark to spy on their target spouses for years.
Despite attempts by officers to destroy them, most of the archives were taken intact after the Wall fell - the old headquarters is now a museum, as is the prison at Hohenschönhausen.
Being people of good humour, the East Germans had numerous jokes about their Big Brothers:
- How can you tell that the Stasi has bugged your apartment? There's a new cabinet in it.
- [GDR General Secretary Erich] Honecker and [Stasi chief Erich] Mielke are discussing their hobbies. Honecker: "I collect all the jokes about me." Mielke: "Well we have almost the same hobby. I round up all those who tell jokes about you."
- What did the Stasi men do after the Reunification? They became taxi drivers, because they already knew where each person lived and everywhere they went.
The Stasi in fiction:
Just about anything that takes place in East Germany has a good chance to include the Stasi.
- The Lives of Others. The central character is an agent of the Stasi who is tasked to monitor the life of a playwright. The actor who plays him was himself spied on by his wife working for them—just like what happens in the film.
- Night Crossing: referred to as the "SSD", or Staatsicherheitdienst.
- Anna Funder's Stasiland is a non-fiction novel following Australian journalist Funder as she collects stories from ex-Stasi men and their victims.
- In Deutschland 83, the main character is forced to infiltrate the West by the Stasi. It's one of the few pieces of media in reunified Germany to show the Stasi in a Grey-and-Grey Morality setting rather than as automatic targets of mockery which led to some Germans disavowing the film.
- In Schwarzesmarken the Stasi serve as the true antagonists in the series compared to the Horde of Alien Locusts that are the BETA by hampering the progress of the NVA and launching a coup for power. Other than the obvious Bug War and their use of Humongous Mecha, they're far less subtle compared to their Real Life counterparts that work in the shadows especially with their villainous traits cranked up to eleven.
- Almost any person who was old enough to have possibly been related to the Stasi in any way shape or form either touts their opposition to them, is denounced as a collaborator, or both. This is especially true for politicians who grew up in East Germany.
- John le Carré mostly wrote about British versus Soviet intelligence, but his mastermind Karla is based on Markus Wolf, who ran the Stasi's foreign intelligence division for nearly the entire existence of the Stasi. More directly, two of his most famous early works, The Spy Who Came in from the Cold and The Looking Glass War, focus directly on British versus East German intelligence rather than British versus Soviet.
- At the beginning of Good Bye, Lenin!, after Alex's father defects to the West, Christiane is interrogated by two Stasi agents. Defection was a serious crime and would have dire consequences for the family. Indeed, Christiane becomes unresponsive for weeks afterwards.
- The Stasi appears as a minor antagonist force in the East Berlin campaign mission of Call of Duty: Black Ops Cold War. Their foreign intelligence service branch, the Main Directorate for Reconnaissance (HVA) also appears in Multiplayer mode as one of Warsaw Pact subfaction along with Soviet KGB and Cuban DGI.
- The Person of Interest episode "Foe" features an ex-Stasi operative who was betrayed by his team as the antagonist. 25 years later, he breaks out of prison, embarking on a Roaring Rampage of Revenge against his own teammates for betraying him and allegedly getting his wife killed.
- The manga Toudoku ni Ita (I Was in East Germany) focused on a special Stasi unit of Super Soldiers, whose creation is hinted to be a leftover project of the Nazis, whose job is stop the rising anti-government groups in East Germany during the 1980s.
- The episode "Music To Die For" of Lewis involved an elderly German man who was murdered by an intruder in his friend's house; the investigation reveals he was murdered by a Stasi informer he had been investigating who had been responsible for the arrest and subsequent death of said friend's father.
- Several Stasi agents appear in Girls' Frontline, where they were reformed in the aftermath of the Collapse Fluid Incidents. Unusually, all Stasi agents in the game are actually allies of the player character, as they oppose both the rogue Neo-Soviet forces and White Faction terrorist group that show up in later events.
- A No Historical Figures Were Harmed example, but the Ostania State Security Service in Spy X Family is the in-universe version, as Ostania is a Fantasy Counterpart Culture to East Germany. They aren't portrayed so much as evil as misguided, though their actions certainly cross several moral lines. Yuri Briar, Yor's brother, is one of their newest recruits. Both Lois and Yor are wary of them, as Loid is the Westalis spy Twilight and Yor the assassin Thorn Princess, making them both major targets for the SSS.