Since well before the days of the Oliver North/Iran Contra shredding debacle, or Enron, there have been both nefarious and legitimate interests in "unshredding," or reconstructing shredded documents.
Identity thieves, spies, and personal enemies or stalkers have been known to dig through trash looking for documents, and shredding is not always a deterrent to the most determined among them.
But what if you're not a spy or a "bad guy," and rather just absentmindedly fed the only copy of your Great American Novel to the shredder? Or perhaps you've shredded an important receipt or record that you now realize you need. Maybe you're a business owner seeking evidence of crime within your own corporation, and the suspects have used shredders to try to cover their tracks. Governments, too, use "unshredding" techniques regularly, as do police detectives, private investigators, lawyers, and other professionals.
For those companies or individuals who wish to unshred what was once shredded, there are services that will attempt to manually reconstruct shredded paper into a replica of its original form. There is even a software product called Unshredder that involves scanning the shredded pieces so they can possibly be reassembled digitally and then printed. The company recommends securing the unorganized strips or "noodles" face up on a sheet of cardstock and then scanning on a flat-bed scanner and then using the Unshredder software. Unshredding via computer has another advantage, in that it leaves the original, shredded materials intact and free of tape of glue, which may be important if they are to be used as evidence.
Reconstruction is easiest when a strip-cut shredder was used. It can be a time-consuming and tedious process, but not impossible. The strips are often the same length, and wide enough that letters and numbers can be read, making it possible to orient the portions correctly and reassemble them like a puzzle.
Cross-cut shredded materials also have a good chance of being reconstructed. Unshredding pieces from a confetti cut machine (which generates about 300) is more challenging, but still can be doable.
Unshredding documents that were destroyed via a microcut or hammermill shredder, especially one resulting in DIN Level 6 (Top Secret/Classified) particles, is virtually impossible. (While a strip-cut shredder turns a sheet of paper into 34 even strips, a micro-cut shredder produces nearly 3,000 pieces.)
According to a 2003 article in The New York Times, " After the takeover of the United States Embassy in Tehran in 1979, Iranian captors laid pieces of documents on the floor, numbered each one and enlisted local carpet weavers to reconstruct them by hand, said Malcolm Byrne of the National Security Archive at George Washington University." Conversely, the German government is using scanning technology to reassemble shredded documents related to the Stasi regime.
The fact that some shredded materials can possibly be reassembled at all serves as a reminder that sensitive documents call for a higher-quality shredder, preferably a micro-cut or better model.