Xinwen Fu - One Cell is Enough to Break Tor's Anonymity
It seems every Black Hat there's a talk about Tor. And every talk ends with a Q&A during which various defenders of Tor state this isn't a new problem, it's already been addressed or mitigated or it's just part of the design.
He stepped through how a Tor connection is made and torn down, each message (called a cell in Tor) that is sent.
Then he presented his research showing how easily someone who controls both the entry and exit node can identify the circuit, breaking the anonymity.
He also showed that by providing free Tor nodes (it's volunteer driven so they won't turn you away) an attacker can increase the chances of holding both the entry and exit node. His research indicates that control of 9% of the routers will result in tracking 60% of the circuits. Small investment with a big return.
