Peek-a-Boo, I Still See You: Why Efficient Traffic Analysis Countermeasures Fail
The authors consider the setting of HTTP traffic over encrypted tunnels, as used to conceal the identity of websites visited by a user. It is well known that Traffic Analysis (TA) attacks can accurately identify the website a user visits despite the use of encryption, and previous paper has looked at specific attack/countermeasure pairings. They provide the first comprehensive analysis of general-purpose TA countermeasures. They show that nine known countermeasures are vulnerable to simple attacks that exploit coarse features of traffic (e.g., total time and bandwidth).