Tor (short for The onion router) is a system intended to enable online anonymity. Tor client software routes Internet traffic through a worldwide volunteer network of servers in order to conceal a user's location or usage from anyone conducting network surveillance or traffic analysis. Using Tor makes it more difficult to trace Internet activity, including "visits to Web sites, online posts, instant messages and other communication forms", back to the user and is intended to protect users' personal freedom, privacy, and ability to conduct confidential business by keeping their internet activities from being monitored.

At the 28th Chaos Communication Congress Brenno de WInter and Friederike Maier spoke with Roger Dingledine the Project Leader of TOR.