Please use this identifier to cite or link to this item: doi:10.22028/D291-26639
Title: Your choice MATor(s) : large-scale quantitative anonymity assessment of Tor path selection algorithms against structural attacks
Author(s): Backes, Michael
Meiser, Sebastian
Slowik, Marcin
Language: English
Year of Publication: 2015
SWD key words: Computersicherheit
Free key words: Tor
anonymity quantification
Tor's path selection
anonymous communication
rigorous guarantees
DDC notations: 004 Computer science, internet
Publikation type: Report
Abstract: In this paper, we present a rigorous methodology for quantifying the anonymity provided by Tor against a variety of structural attacks, i.e., adversaries that compromise Tor nodes and thereby perform eavesdropping attacks to deanonymize Tor users. First, we provide an algorithmic approach for computing the anonymity impact of such structural attacks against Tor. The algorithm is parametric in the considered path selection algorithm and is, hence, capable of reasoning about variants of Tor andalternative path selection algorithms as well. Second, we present formalizations of various instantiations of structural attacks against Tor and show that the computed anonymity impact of each of theseadversaries indeed constitutes a worst-case anonymity bound for the cryptographic realization of Tor. Third, we use our methodology to conduct a rigorous, large-scale evaluation of Tor's anonymity which establishes worst-case anonymity bounds against various structural attacks for Tor and for alternative path selection algorithms such as DistribuTor, SelekTOR, and LASTor. This yields the rst rigorous anonymity comparison between dierent path selection algorithms. As part of our analysis, we quantify the anonymity impact of a path selection transition phase, i.e., a small number of users decides to run an alternative algorithm while the vast majority still uses the original one. The source code of our implementation is publicly available.
Link to this record: urn:nbn:de:bsz:291-scidok-63378
Series name: Technischer Bericht / A / Fachbereich Informatik, Universität des Saarlandes
Series volume: 2015/03
Date of registration: 8-Jan-2016
Faculty: MI - Fakultät für Mathematik und Informatik
Department: MI - Informatik
Collections:SciDok - Der Wissenschaftsserver der Universität des Saarlandes

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