Here at Chad’s News, we’ve previously mentioned Tor, a network used for anonymous communication on the internet. Volunteers host Tor servers, and a user’s internet traffic is routed through those servers, thus disguising the actual location of the sender. (NOTE: Never, ever, ever host a Tor server on a computer that you wouldn’t want confiscated by law enforcement.) Tor has been touted as a great method for political dissidents, whistle-blowers, and others to confidentially send information via the internet without being identified. Of course, it’s also used for illegal traffic.
The linked article discusses a paper [PDF] (Users Get Routed: Traffic Correlation on Tor by Realistic Adversaries, lead author Aaron Johnson of the US Naval Research Laboratory) that comes to some startling conclusions about Tor anonymity. If someone uses Tor regularly, an adversary with significant resources (e.g., a government) has a high chance (80% to 95%) of successfully tracing that user over a period of 3 to 6 months.