Traffic Confirmation Attacks Despite Noise

TL;DR

This paper presents a traffic confirmation attack on low-latency mix networks using robust hashing, achieving high accuracy even with network impairments and advanced padding, highlighting vulnerabilities.

Contribution

The authors adapt the Coskun-Memon Algorithm for real-time traffic hashing and demonstrate its effectiveness against padding schemes in low-latency networks.

Findings

80% true positive rate for matching one flow among 9000 with <2% false positives

Over 90% match rate against probabilistic padding schemes

Attack remains effective despite network impairments

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.