The Tor network allows anonymity online. It was designed to conceal identifying information while browsing the web, but can be used to anonymize any TCP traffic. The basic mechanism is to relay a user's traffic through a series of volunteer routers around the world. In this way, the traffic of many different users is mixed together, making it difficult to tell who sent what. This is useful to ensure the free exchange of information without fear of reprisal. Tor is used by whistleblowers to report wrongdoing, citizens of China to evade government censorship of the media, and citizens concerned about their privacy online.
Perhaps the largest barrier to more widespread adoption of Tor is the latency it incurs. Browsing the internet over Tor is much slower than browsing without it. Some of this latency is unavoidable, such as the time required to route information through the volunteer routers. If the routers lie on different continents, this travel time can be significant. However, the other sources of latency can be reduced. Specifically, we have found that the design decision to use TCP connections between each pair of routers causes packets to spend far too much time waiting in buffers. By using DTLS, a simpler, faster protocol, we have greatly reduced this unneccessary delay.
Since a fundamental feature of Tor is its ability to blend traffic from around the world, we required a global network in order to test our improvements. We are using PlanetLab to test both the standard Tor code and our altered version, and measure the performance of each. We will also be testing the interoperability of the two versions, to allow an easy integration of our improvements into the current network.
If you have any questions about this project, please contact either:
- Prof. Ian Goldberg, the PI for Waterloo's PlanetLab nodes
- Chris Alexander, currently developing and maintaining the code base
