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San Francisco Team Wins DARPA's De-Shredding Contest
New submitter karlnyberg writes with an update to the recently announced de-shredding challenge posted by DARPA: "The team 'All Your Shreds Are Belong To U.S.' has correctly solved all five puzzles, and the Challenge has now ended. You may view the winning team's submissions as well as the complete puzzle solutions by following the links on our homepage. We recognize that many of our participants have devoted countless hours to painstakingly piecing our puzzles back together, and we truly appreciate everyone's efforts. Hopefully you enjoyed the Challenge and learned something new along the way. We certainly did!"
The test was actually much simpler than any real-world application might be. Each puzzle was really only one or two (or a few) shredded pages, with various degrees of shredding and various bits of writing. It is a first step, but nowhere near what you would be dealing with in any real-world situation where hundreds or thousands of pages of shredded documents would be mixed together.
I participated (a bit) with the UCSD team that basically made a crowd-sourced jigsaw puzzle to do it - at last check they were in the top 5, but I don't think they got the last puzzle (yet). This approach seems reasonable for the relatively simple puzzles of the challenge, but it really wouldn't scale very well - requires a lot of labor.
It sounds like the winning team had a much better (and more scaleable) strategy, where an algorithm scores all of the pieces for fit in a particular place and then allows the user(s) to choose the best piece from a few high-scoring ones. While I still don't think this would work very well in a real-world scenario, obviously it would work better than depending on massive crowd sourcing.
NSA-approved shredders are good enough for destroying classified documents up to TS; the shredded remains do not need to be controlled. The shreddings are fine enough that no piece of output can contain a single glyph at any reasonable font size. The shreddings of even a single piece of paper are shuffled together by the action of the blades. These shredders aren't cheap, but I bet they'll stand up to state-level threats of reconstruction for the next 10 years or so.
If that's not good enough, some locations use burn-boxes - never trust a machine to do thermodynamic's job!