DARPA scanned the shreds. The funny thing is, they didn't want to shred the original paper, so first they photocopied the paper in a high quality color copier, shredded it, and scanned it. And that's where the little yellow dots came from. :D
Did they scan both sides of the shreds?
interesting. now my brain is churning on why would they not want the originals shredded. what does that say about the value they placed on the originals? why would they open a contest up with documents of such perceived value as the content? being DARPA, i'm sure there's a reason though