49-page NSA research paper on how to crack Tor
apps.washingtonpost.com
apps.washingtonpost.com
Yet there was an attack (on an older version of Tor) published openly not long before this paper was written. (http://www.onion-router.net/Publications/locating-hidden-ser...)
So the NSA was unable to independently discover what's in the above paper. Or they discovered it, but it was at a higher cleared level than this leaked paper.
The "Locating Hidden Servers" paper has a .mil author too.