Abstract:

In anonymous communications, as in other fields of computer security, the study of attack and defence go hand in hand. It might therefore seem strange that, until recently, the study of "traffic analysis" has not attracted a lot of attention. In this talk, recent quantitative breakthroughs are presented in understanding how traffic analysis is performed. They are used to quantify the cost of attacking generic anonymous communication systems. The focus then shifts towards high-bandwidth low-latency systems like "onion routing". We show how the features remaining in the anonymised streams of traffic can be used to trace them, and provide techniques that scale to de-anonymise whole networks.