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Research Spending & Results

Award Detail

Doing Business As Name:Princeton University
  • Prateek Mittal
  • (609) 258-3090
Award Date:08/19/2014
Estimated Total Award Amount: $ 250,000
Funds Obligated to Date: $ 250,000
  • FY 2014=$250,000
Start Date:09/01/2014
End Date:08/31/2017
Transaction Type:Grant
Awarding Agency Code:4900
Funding Agency Code:4900
CFDA Number:47.070
Primary Program Source:040100 NSF RESEARCH & RELATED ACTIVIT
Award Title or Description:TWC: Small: Collaborative: Advancing Anonymity Against an AS-level Adversary
Federal Award ID Number:1423139
DUNS ID:002484665
Parent DUNS ID:002484665
Program:Secure &Trustworthy Cyberspace
Program Officer:
  • Nina Amla
  • (703) 292-7991

Awardee Location

Street:Off. of Research & Proj. Admin.
Awardee Cong. District:12

Primary Place of Performance

Organization Name:Princeton University
Street:87 Prospect Avenue, 2nd Floor
Cong. District:12

Abstract at Time of Award

Autonomous systems (AS) are key building blocks of the Internet's routing infrastructure. Surveillance of AS may allow large-scale monitoring of Internet users. Those who aim to protect the privacy of their online communications may turn to anonymity systems like Tor, but Tor is not designed to protect against such AS-level adversaries. AS-level adversaries present unique challenges for the design of robust anonymity systems and present a very different threat model from the ones used to design and study systems like Tor. Thus, new research is needed to understand this threat and to defend against it. This project is investigating the design of anonymity systems that are resilient against AS-level adversaries. First, the project aims to quantify the capabilities of AS-level adversaries, who are powerful eavesdroppers and also capable of active attacks, but also have some limitations in practice. Second, the project is designing new route-selection strategies for anonymity systems that can limit how much of the anonymized traffic the AS-level adversary can observe and attack. Finally, the project is investigating how anonymity systems can hinder an AS-level adversaries' ability to analyze encrypted traffic by injecting spurious cover traffic and timing delays. The findings and new anonymity system designs from this research will impact the privacy of a broad class of users in the context of forms of large-scale monitoring of online communications.

Publications Produced as a Result of this Research

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Changchang Liu, Peng Gao, Matthew Wright, and Prateek Mittal "Exploiting Temporal Dynamics in Sybil Defenses" ACM CCS, v., 2015, p..

Yixin Sun, Anne Edmundson, Nick Feamster, Mung Chiang, Prateek Mittal "Counter-RAPTOR: Safeguarding Tor Against Active Routing Attacks" IEEE Security and Privacy 2017, v., 2017, p..

Yushan Liu, Shouling Ji, and Prateek Mittal "SmartWalk: Enhancing Social Network Security via Adaptive Random Walks" ACM CCS, v., 2016, p..

Project Outcomes Report


This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

The major goal of the project was to advance the science of anonymous communication against the threat of Autonomous System (AS)-level adversaries. First, we investigated traffic analysis attacks that AS-level adversaries can perform, and second, we investigated defenses against such attacks based on novel path selection algorithms and cover traffic. 

The project has lead to significant impact on society, since anonymity systems such as the Tor network are used by millions of users to protect their privacy. For example, Tor is widely used by law-enforcement, intelligence agencies, political dissidents, business, journalists, and ordinary citizens. Our RAPTOR attacks inform this audience that Tor is not as anonymous as previously reported. We demonstrated the feasibility of Raptor attacks in which an adversary can perform active routing attacks to compromise the privacy of Tor users. Our Counter-RAPTOR defenses will enhance the privacy received by such users from anonymity systems including Tor. Counter-RAPTOR defenses proactively protect Tor users against routing attacks, and monitor the BGP routing protocol to detect anomalies. 

Our project led to direct societal impact, as Counter-RAPTOR defenses are being integrated into the Tor metrics portal, and the Let's Encrypt certificate authority deployed our suggested countermeasures to mitigate the threat of active routing attacks. Finally, the project provided significant training opportunities for both graduate and undergraduate students at Princeton University.  


Last Modified: 02/19/2018
Modified by: Prateek Mittal

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