Computers piece together millions of shredded Stasi documents

A moving and intriguing Wired feature tells the story of the activists, hackers and engineers who are working to un-shred millions of hand-shredded secret files that the East German Stasi ripped to pieces in the run-up to the collapse of the Berlin Wall. The secret police panicked when they realized that they were about to lose their tight rein on power and shredded as much as they could — but they had collected more files than any other bureaucracy in the history of the world, and they couldn't shred fast enough. So they assigned a detail to go into the basement, into a secure, copper-lined computing room, and hand-tear the most sensitive documents, all day long, millions of them.

The liberators of the Stasi's archive saved the hand-shredded material and now computer scientists are working to piece it all back together, using clever algorithms reminiscent of the systems described in Vernor Vinge's groundbreaking novel Rainbows End. The description of the files themselves are incredible — one activist had sixty binders compiled on her, comprising every movement she took (she was followed constantly by crew-cut secret police in white vans who'd crawl the curb a few metres behind her as she walked down the street).

The data for the 400-bag pilot project is stored on 22 terabytes worth of hard drives, but the system is designed to scale. If work on all 16,000 bags is approved, there may be hundreds of scanners and processors running in parallel by 2010. (Right now they're analyzing actual documents, but still mostly vetting and refining the system.) Then, once assembly is complete, archivists and historians will probably spend a decade sorting and organizing. "People who took the time to rip things up that small had a reason," Nickolay says. "This isn't about revenge but about understanding our history." And not just Germany's – Nickolay has been approached by foreign officials from Poland and Chile with an interest in reconstructing the files damaged or destroyed by their own repressive regimes…

The truth is, for Poppe the reconstructed documents haven't contained bombshells that are any bigger than the information in the rest of her file. She chooses a black binder and sets it down on the glass coffee table in her living room. After lighting a Virginia Slim, she flips to a page-long list of snitches who spied on her. She was able to match codenames like Carlos, Heinz, and Rita to friends, coworkers, and even colleagues in the peace movement. She even tracked down the Stasi officer who managed her case, and after she set up a sort of ambush for him at a bar – he thought he was there for a job interview – they continued to get together. Over the course of half a dozen meetings, they talked about what she found in her files, why the Stasi was watching her, what they thought she was doing. For months, it turned out, an agent was assigned to steal her baby stroller and covertly let the air out of her bicycle tires when she went grocery shopping with her two toddlers. "If I had told anyone at the time that the Stasi was giving me flat tires, they would have laughed at me," she says. "It was a way to discredit people, make them seem crazy. I doubted my own sanity sometimes." Eventually, the officer broke off contact, but continued to telephone Poppe – often drunk, often late at night, sometimes complaining about his failing marriage. He eventually committed suicide.