Traffic Confirmation Attacks Despite Noise

Abstract: We propose a traffic confirmation attack on low-latency mix networks based on computing robust real-time binary hashes of network traffic flows. Firstly, we adapt the Coskun-Memon Algorithm to construct hashes that can withstand network impairments to allow fast matching of network flows. The resulting attack has a low startup cost and achieves a true positive match rate of 80% when matching one flow out of 9000 with less than 2% false positives, showing traffic confirmation attacks can be highly accurate even when only part of the network traffic flow is seen. Secondly, we attack probabilistic padding schemes achieving a match rate of over 90% from 9000 network traffic flows, showing advanced padding techniques are still vulnerable to traffic confirmation attacks.