Shredded Documents Brought Back to Life

Troops often find fragments of destroyed documents in war zones. Putting the pieces back together to collect coherent information is the difficult part.

The Defense Advanced Research Projects Agency has begun an initial investigation into information security on the battlefield — how U.S. data might be vulnerable and how troops could use confiscated scraps to gather intelligence.

The agency recently had nearly 9,000 teams of computer scientists and puzzle aficionados take part in a “shredder” competition to see who could piece together five destroyed messages. Three programmers based in San Francisco won the competition by reconstructing all of the documents using custom-coded, computer-vision algorithms that suggested fragment pairings for the team to verify. It took the winning team — which called itself “All Your Shreds Are Belong To U.S.” — 600 man-hours to piece together the documents, which had been shredded into more than 10,000 pieces.

“Lots of experts were skeptical that a solution could be produced at all let alone within the short timeframe,” said Dan Kaufman, director of DARPA’s information innovation office. “The most effective approaches were not purely computational or crowd-sourced, but used a combination blended with some clever detective work.”

The challenge began on Oct. 27 and ended Dec. 2. Some of the shreds featured straightforward messages in paragraph form. One included a sketch of a city, with geographic coordinates and distances between certain locations in the margin. The final puzzle alone consisted of three pages of a handwritten note shredded into more than 6,000 pieces. One of the pages was shredded in the opposite direction of the other two, and all three had at least one message in Morse code.

Topics: Science and Engineering Technology