See the article: NSA and GCHQ target Tor network that protects anonymity of web users (Guardian, link) And see: Attacking Tor: how the NSA targets users' online anonymity (Guardian, link)
See the article: NSA and GCHQ target Tor network that protects anonymity of web users (Guardian, link)
And see: Attacking Tor: how the NSA targets users’ online anonymity (Guardian, link)