NavigaTor: Finding Faster Paths to Anonymity

R. Annessi, M Schmiedecker:
"NavigaTor: Finding Faster Paths to Anonymity";
Vortrag: 1st IEEE European Symposium on Security and Privacy, Saarbr├╝cken; 21.03.2016 - 24.03.2016; in:"IEEE European Symposium on Security and Privacy (Euro S&P)", (2016), 13 S.

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The Tor network is currently by far the most pop-
ular system for providing anonymity on the Internet. Even
though both latency and throughput have been significantly
improved in recent years, Tor users still experience variable
delays on connecting to servers. Such delays have been shown
to be especially harmful for browsing the web and prevent
altogether the use of protocols where a certain quality of service
is indispensable.
In this paper we propose and evaluate methods to measure
and improve performance in the Tor network. To estimate the
quality of circuits for future traffic, we use active Round-Trip-
Time (RTT) measurements and a-priori information of the
distribution of RTT values. In this way, slow circuits can be
discarded before having negative impact on user experience.
Using NavigaTor, our high performance measurement software
which includes a custom Tor path generator, we are the
first to conduct large-scale performance measurements on the
live Tor network, building millions of circuits within days,
without stressing the anonymity network. As part of our study,
we conduct several experiments from PlanetLab on the live
Tor network to analyze the trade-off between the quality of
protection and the quality of service. We compare our Circuit-
RTT method to the current state-of-the-art method Circuit
Build Time (CBT) and the more recently proposed congestion-
aware scheme, finding that the congestion-aware scheme in
its original design achieves only minor improvements on the
current Tor network and that Circuit-RTT improves latency
and throughput more effectively than CBT.