48 research outputs found
Anonymous web browsing through predicted pages
Anonymous web browsing is an emerging hot topic with many potential applications for privacy and security. However, research on low latency anonymous communication, such as web browsing, is quite limited; one reason is the intolerable delay caused by the current dominant dummy packet padding strategy, as a result, it is hard to satisfy perfect anonymity and limited delay at the same time for web browsing. In this paper, we extend our previous proposal on using prefetched web pages as cover traffic to obtain perfect anonymity for anonymous web browsing, we further explore different aspects in this direction. Based on Shannon’s perfect secrecy theory, we formally established a mathematical model for the problem, and defined a metric to measure the cost of achieving perfect anonymity. The experiments on a real world data set demonstrated that the proposed strategy can reduce delay more than ten times compared to the dummy packet padding methods, which confirmed the vast potentials of the proposed strategy.<br /
Toward Anonymity in Delay Tolerant Networks: Threshold Pivot Scheme
Proceedings of the Military Communications Conference (MILCOM 2010), San Jose, CA, October 2010.Delay Tolerant Networks (DTNs) remove traditional assumptions of end-to-end connectivity, extending network communication to intermittently connected mobile, ad-hoc, and vehicular environments. This work considers anonymity as a vital security primitive for viable military and civilian DTNs. DTNs present new and unique anonymity challenges since we must protect physical location information as mobile nodes with limited topology knowledge naturally mix. We develop a novel Threshold Pivot Scheme (TPS) for DTNs to address these challenges and provide resistance to traffic analysis, source anonymity, and sender-receiver unlinkability. Reply techniques adapted from mix-nets allow for anonymous DTN communication, while secret sharing provides a configurable level of anonymity that enables a balance between security and efficiency. We evaluate TPS via simulation on real-world DTN scenarios to understand its feasibility, performance, and overhead while comparing the provided anonymity against an analytically optimal model
Conscript Your Friends into Larger Anonymity Sets with JavaScript
We present the design and prototype implementation of ConScript, a framework
for using JavaScript to allow casual Web users to participate in an anonymous
communication system. When a Web user visits a cooperative Web site, the site
serves a JavaScript application that instructs the browser to create and submit
"dummy" messages into the anonymity system. Users who want to send non-dummy
messages through the anonymity system use a browser plug-in to replace these
dummy messages with real messages. Creating such conscripted anonymity sets can
increase the anonymity set size available to users of remailer, e-voting, and
verifiable shuffle-style anonymity systems. We outline ConScript's
architecture, we address a number of potential attacks against ConScript, and
we discuss the ethical issues related to deploying such a system. Our
implementation results demonstrate the practicality of ConScript: a workstation
running our ConScript prototype JavaScript client generates a dummy message for
a mix-net in 81 milliseconds and it generates a dummy message for a
DoS-resistant DC-net in 156 milliseconds.Comment: An abbreviated version of this paper will appear at the WPES 2013
worksho
Defending Tor from Network Adversaries: A Case Study of Network Path Prediction
The Tor anonymity network has been shown vulnerable to traffic analysis
attacks by autonomous systems and Internet exchanges, which can observe
different overlay hops belonging to the same circuit. We aim to determine
whether network path prediction techniques provide an accurate picture of the
threat from such adversaries, and whether they can be used to avoid this
threat. We perform a measurement study by running traceroutes from Tor relays
to destinations around the Internet. We use the data to evaluate the accuracy
of the autonomous systems and Internet exchanges that are predicted to appear
on the path using state-of-the-art path inference techniques; we also consider
the impact that prediction errors have on Tor security, and whether it is
possible to produce a useful overestimate that does not miss important threats.
Finally, we evaluate the possibility of using these predictions to actively
avoid AS and IX adversaries and the challenges this creates for the design of
Tor
Dovetail: Stronger Anonymity in Next-Generation Internet Routing
Current low-latency anonymity systems use complex overlay networks to conceal
a user's IP address, introducing significant latency and network efficiency
penalties compared to normal Internet usage. Rather than obfuscating network
identity through higher level protocols, we propose a more direct solution: a
routing protocol that allows communication without exposing network identity,
providing a strong foundation for Internet privacy, while allowing identity to
be defined in those higher level protocols where it adds value.
Given current research initiatives advocating "clean slate" Internet designs,
an opportunity exists to design an internetwork layer routing protocol that
decouples identity from network location and thereby simplifies the anonymity
problem. Recently, Hsiao et al. proposed such a protocol (LAP), but it does not
protect the user against a local eavesdropper or an untrusted ISP, which will
not be acceptable for many users. Thus, we propose Dovetail, a next-generation
Internet routing protocol that provides anonymity against an active attacker
located at any single point within the network, including the user's ISP. A
major design challenge is to provide this protection without including an
application-layer proxy in data transmission. We address this challenge in path
construction by using a matchmaker node (an end host) to overlap two path
segments at a dovetail node (a router). The dovetail then trims away part of
the path so that data transmission bypasses the matchmaker. Additional design
features include the choice of many different paths through the network and the
joining of path segments without requiring a trusted third party. We develop a
systematic mechanism to measure the topological anonymity of our designs, and
we demonstrate the privacy and efficiency of our proposal by simulation, using
a model of the complete Internet at the AS-level
Characterising Dependency in Computer Networks using Spectral Coherence
The quantification of normal and anomalous traffic flows across computer networks is a topic of pervasive interest in network se- curity, and requires the timely application of time-series methods. The transmission or reception of packets passing between computers can be represented in terms of time-stamped events and the resulting activity understood in terms of point-processes. Interestingly, in the disparate do- main of neuroscience, models for describing dependent point-processes are well developed. In particular, spectral methods which decompose second-order dependency across different frequencies allow for a rich characterisation of point-processes. In this paper, we investigate using the spectral coherence statistic to characterise computer network activ- ity, and determine if, and how, device messaging may be dependent. We demonstrate on real data, that for many devices there appears to be very little dependency between device messaging channels. However, when sig- nificant coherence is detected it appears highly structured, a result which suggests coherence may prove useful for discriminating between types of activity at the network level