The German broadcaster ARD published a report that reveals that NSA XKeyscore has targeted two Germany-based Tor Directory Authority servers. The broadcaster published for the first time the source code from XKeystore has been revealed. The NSA boasts in training materials that the program is its widest-reaching system for developing intelligence from the internet. Since 2008 the X-Keyscore platform was used to track activities related to 300 alleged terrorists around the world studying their habits and participations to various Internet forums.”]
Source: http://securityaffairs.co/wordpress/26335/intelligence/xkeyscore-hit-tor-authority-server.html