Nicholas J. Hopper

Associate Professor
Computer Science & Engineering Department
University of Minnesota
hopper at cs umn edu

Office:
4211 Keller Hall
(612)-626-1284 
Shortcuts: Research interests | Papers | Teaching | Etc...


Research

My general interests are in cryptography, computer & network security, and theoretical computer science.   The focus of my research is on proving the security of computer systems and protocols.  The central questions in this research are:
The main application areas to which my research applies these questions are privacy and anonymity and peer-to-peer systems.  I have had the privilege of working on these subjects with many bright students.

Papers

Journals

Eugene Y. Vasserman and Nicholas Hopper. "Vampire attacks: Draining life from wireless ad-hoc networks," IEEE Transactions on Mobile Computing, 12(2): 318-332, February 2013.

Eric Chan-Tin, Victor Heorhiadi, Nicholas Hopper, and Yongdae Kim. "The Frog-Boiling Attack: Limitations of Secure Network Coordinate Systems." ACM Transactions on Information and Systems Security (TISSEC), 14(3):1-28, November 2011.

Nicholas Hopper, Eugene Y. Vasserman, and Eric Chan-Tin. "How much anonymity does network latency leak?" ACM Transactions on Information and System Security (TISSEC), 13(2):1-28, February 2010. ( 2010 ACM)

Peng Wang, James Tyra, Eric Chan-Tin, Tyson Malchow, Denis Foo Kune, Nicholas Hopper,  and Yongdae Kim. "Attacking the kad network - real world evaluation and high fidelity simulation using DVN" Security and Communication Networks, 2009.

Nicholas Hopper, Luis von Ahn, and John Langford. "Provably Secure Steganography," IEEE Transactions on Computers 58(5): 662-676, May 2009. (2009 IEEE)

Eugene Y. Vasserman, Nicholas Hopper, and James Tyra. "SilentKnock: practical, provably undetectable authentication." International Journal of Information Security 8(2): 121-135, April 2009. 

Jung Hee Cheon, Nicholas Hopper, Yongdae Kim and Ivan Osipkov. "Provably Secure Timed-Release Public Key Encryption." ACM Transactions on Information and System Security (TISSEC) 11(2):1-44, March 2008.  ( 2008 ACM)

Peer-reviewed Conference/Workshops

Hong Liu, Eugene Vasserman, and Nicholas Hopper. "Improved Group Off-The-Record Messaging" at WPES 2013.

John Geddes, Maxfield Schuchard, and Nicholas Hopper. "Cover Your ACKs: Pitfalls of Covert Channel Based Censorship Circumvention," at CCS 2013.

John Geddes, Rob Jansen, and Nicholas Hopper. "How Low Can You Go: Balancing Performance with Anonymity in Tor," at PETS 2013.

Maxfield Schuchard, Christopher Thompson, Nicholas Hopper and Yongdae Kim. "Peer Pressure: Exerting Malicious Influence on Routers at a Distance," at ICDCS 2013.

Qiyan Wang, Zi Lin, Nikita Borisov and Nicholas Hopper. "rBridge: User Reputation based Tor Bridge Distribution with Privacy Preservation," at NDSS 2013.

Maxfield Schuchard, John Geddes, Christopher Thompson and Nicholas Hopper. "Routing Around Decoys," at CCS 2012.

Zi Lin and Nicholas Hopper. "New Attacks on Timing-based Network Flow Watermarks," at USENIX Security 2012.

Rob Jansen, Paul Syverson and Nicholas Hopper. "Throttling Tor Bandwidth Parasites," at USENIX Security 2012.

Rob Jansen, Kevin Bauer, Nicholas Hopper and Roger Dingledine. "Methodically Modeling the Tor Network," at CSET 2012.

Eugene Vasserman, Victor Heorhiadi, Nicholas Hopper and Yongdae Kim. "One-way indexing for plausible deniability in censorship resistant storage," at FOCI 2012.

Abedelaziz Mohaisen, Huy Tran, Nicholas Hopper and Yongdae Kim. "On the Mixing Time of Directed Social Graphs and Security Implications," at ASIACCS 2012.

Eric Chan-Tin and Nicholas Hopper. "KoNKS: Konsensus-style Network Koordinate System," at ASIACCS 2012.

Zi Lin, Denis Foo Kune and Nicholas Hopper. "Efficient Private Proximity Testing with GSM Location Sketches," at Financial Crypto 2012.

Rob Jansen and Nicholas Hopper. "Shadow: Running Tor in a Box for Accurate and Efficient Experimentation," at NDSS 2012.  Also available as UMN Tech Report 11-020.

Denis Foo Kune, John Koelndorfer, Nicholas Hopper and Yongdae Kim.  "Location leaks over the GSM air interface," at NDSS 2012.

Peter Lofgren and Nicholas Hopper.  "FAUST: Efficient, TTP-Free Abuse Prevention by Anonymous Whitelisting," at WPES 2011.

Abedelaziz Mohaisen, Nicholas Hopper, and Yongdae Kim.  "Keep your friends close: Incorporating Trust into social network-based Sybil defenses," at INFOCOM 2011.

Peter Lofgren and Nicholas Hopper.  "BNymble (A short paper): More anonymous blacklisting at almost no cost," at Financial Crypto 2011.

Eric Chan-Tin and Nicholas Hopper. "Accurate and Provably Secure Latency Estimation with Treeple," at NDSS 2011.

Max Schuchard, Eugene Vasserman, Abedelaziz Mohaisen, Denis Foo Kune, Nicholas Hopper, and Yongdae Kim.  "Losing Control of the Internet: Using the Data Plane to Attack the Control Plane," at NDSS 2011.

Rob Jansen, Nicholas Hopper, and Yongdae Kim.  "Recruiting New Tor Relays with BRAIDS," at CCS 2010.

Zi Lin and Nicholas Hopper. "Jack: Scalable Accumulator-Based Nymble System," at WPES 2010.

Max Schuchard, Alexander W.  Dean, Victor Heorhiadi, Nicholas Hopper, and Yongdae Kim. "Balancing the Shadows," at WPES 2010.

Jon McLachlan, Andrew Tran, Nicholas Hopper, and Yongdae Kim. "Scalable onion routing with Torsk," at  CCS 2009.

Eugene Vasserman, Rob Jansen, James Tyra, Nicholas Hopper and Yongdae Kim. "Membership-concealing overlay networks," at  CCS 2009.

Jon McLachlan and Nicholas Hopper. "On the risks of serving whenever you surf: Vulnerabilities in Tor's blocking resistance design," at WPES 2009.

Andrew Tran, Nicholas Hopper and Yongdae Kim. "Hashing it out in public: Common failure modes of DHT-based anonymity schemes," at WPES 2009.

Eric Chan-Tin, Daniel Feldman, Yongdae Kim and Nicholas Hopper. "The Frogboiling attack: limitations of anomaly detection for secure network coordinates," at SecureComm 2009.

Hun-Jeong Kang, Eric Chan-Tin, Yongdae Kim and Nicholas Hopper. "Why Kad Lookup Fails," at P2P09.

B. Kang et al. "Towards Complete Node Enumeration in a Peer-to-Peer Botnet," at ASIACCS 2009.

P. Wang,  J. Tyra,  E. Chan-Tin, T. Malchow, D. Foo Kune, N. Hopper and Y. Kim.  "Attacking the Kad Network," at SecureComm 2008.

Erik Shimshock, Matthew Staats, and Nicholas Hopper. "Breaking and Provably Fixing Minx," at PET 2008.

Jon McLachlan and Nicholas Hopper. "Don't Clog the Queue: Circuit Clogging and Mitigation in P2P anonymity schemes," at Financial Crypto 2008.

Nicholas Hopper, Eugene Y. Vasserman, and Eric Chan-Tin. "How much anonymity does network latency leak?" at CCS 2007.

Eugene Vasserman, Nicholas Hopper, John Laxson, and James Tyra.  "SilentKnock: Practical and Provably Undetectable Authentication." at ESORICS 2007.

Ivan Osipkov, Eugene Vasserman, Nicholas Hopper and Yongdae Kim. "Combatting Double-Spending Using Cooperative P2P Systems." at ICDCS 2007.

Nicholas Hopper, David Molnar, and David Wagner.  "From Weak to Strong Watermarking." at 4th Theoretical Cryptography Conference: TCC 2007(Full version)

Nicholas Hopper and Eugene Vasserman. "On the effectiveness of k-anonymity against traffic analysis and surveillance," at Privacy in the Electronic Society: WPES 2006.

Luis von Ahn, Andrew Bortz, Nicholas Hopper, and Kevin O'Neill.  "Selectively Traceable Anonymity," at Privacy Enhancing Technologies: PET 2006.

Ivan Osipkov, Peng Wang, Nicholas Hopper and Yongdae Kim.  "Robust Accounting in Decentralized P2P Storage Systems," at ICDCS 2006.

Jung Hee Cheon, Nicholas Hopper, Yongdae Kim and Ivan Osipkov.  "Authenticated Key-Insulated Public Key Encryption and Timed-Release Cryptography," at Financial Crypto 2006.

Nicholas Hopper. "On Steganographic Chosen Covertext Security," at ICALP 2005.

Luis von Ahn, Nicholas J. Hopper, and John Langford. "Covert Two-Party Computation," at STOC 2005.

Luis von Ahn and Nicholas J. Hopper. " Public-Key Steganography," at Eurocrypt 2004.

Luis von Ahn, Andrew Bortz, and Nicholas J. Hopper. "k-Anonymous Message Transmission," at CCS 2003.

Luis von Ahn, Manuel Blum, Nicholas J. Hopper and John Langford. " CAPTCHA: Using Hard AI Problems for Security," at Eurocrypt 2003.

Nicholas J. Hopper, John Langford, and Luis Von Ahn. " Provably Secure Steganography," at Crypto 2002.

Nicholas J. Hopper and Manuel Blum. " Secure Human Identification Protocols," at Asiacrypt 2001.

Nicholas J. Hopper, Sanjit A. Seshia, and Jeanette M. Wing, "Combining Theory Generation and Model Checking for Security Protocol Analysis," at Formal Methods in Computer Security, July 2000. Also available as CMU Technical Report CMU-CS-00-107, January 2000.

Nicholas Freitag McPhee and Nicholas J. Hopper. " Analysis of Genetic Diversity through Population History," in GECCO99: Proceedings of the Genetic and Evolutionary Computation Conference, July 1999.

Nicholas Freitag McPhee and Nicholas J. Hopper. " AppGP: An alternative structural representation for GP," in Proceedings of the 1999 Congress on Evolutionary Computation, June 1999.

Nicholas Freitag McPhee, Nicholas J. Hopper, and Mitchell L. Reierson. " Impact of types on essentially typeless problems in GP," in Genetic Programming 1998: Proceedings of the Third Annual Conference, July 1998.

Peer-Reviewed Conference Posters and Abstracts

Max Schuchard, Chris Thompson, Nicholas Hopper and Yongdae Kim. "Taking Routers off their Meds: Why Assumptions of Router Stability are Dangerous," in NDSS'12 Chair's Invited Session.

Rob Jansen, Paul Syverson, and Nicholas Hopper. "Throttling Tor Bandwidth Parasites," in NDSS'12 Chair's Invited Session.  Full version available as UMN Tech Report 11-019.

Abedelaziz Mohaisen, Nicholas Hopper, and Yongdae Kim. "Designs to Account for Trust in Social Network-based Sybil Defenses," in CCS'10/Posters.

Eric Chan-Tin and Nicholas Hopper. "Secure Latency Estimation with Treeple," in CCS'10/Posters.

Max Schuchard, Abdelaziz Mohaisen, Denis Foo Kune, Nicholas Hopper, Yongdae Kim, and Eugene Vasserman.  "Losing Control of the Internet: Using the Data Plane to Attack the Control Plane," in CCS'10/Posters.

In submission

Please send e-mail if you are interested in any of the following:


Other

Eugene Y. Vasserman, Victor Heorhiadi, Yongdae Kim,  and Nicholas Hopper. "Censorship resistant overlay publishing", 2011.  UMN Tech Report 11-027.

Peng Wang, Ivan Osipkov, Nicholas Hopper, and Yongdae Kim.  "Myrmic: Provably secure and efficient DHT routing," DTC Technical Report, 2006.

Nicholas J. Hopper. "Toward a Theory of Steganography," CMU Ph.D. Thesis, 2004.

Nicholas J. Hopper and Manuel Blum, "A Secure Human-Computer Authentication Scheme", CMU Technical Report CMU-CS-00-139, May 2000.


Teaching

At Minnesota:
Spring 2013 - CSci 5471: Modern Cryptography.
Spring 2013 - CSci 4011: Inherent Limitations of Computer Programs.
Fall 2012- CSci 5271: Introduction to Computer Security.
Spring 2012 - CSci 4011: Inherent Limitations of Computer Programs.
Fall 2011 - CSci 5271: Overview of Computer Science.
Spring 2011 - CSci 1001: Overview of Computer Science.
Fall 2010 - CSci 5271: Introduction to Computer Security.
Fall 2010 - CSci 8980: Advanced Cryptography Seminar.
Spring 2010 - CSci 5403: Complexity Theory.
Fall 2009 - CSci 5271: Introduction to Computer Security.
Spring 2009 - CSci 4011: Inherent Limitations of Computer Programs.
Fall 2008 - CSci 5271: Introduction to Computer Security.
Spring 2008 - CSci 5403: Complexity Theory.
Fall 2007 - CSci 5271: Introduction to Computer Security.
Spring 2007 - CSci 4011: Formal Languages and Automata Theory.
Fall 2006 -  CSci 5271: Introduction to Computer Security.
Spring 2006 -  CSci 4011: Formal Languages and Automata Theory.
Fall 2005 -  CSci 5271: Introduction to Computer Security.
Spring 2005 -  CSci 8980: Advanced Cryptography.

At CMU:
Spring 2003 - 15-859I Theoretical Aspects of Cryptography
Fall 2001 -  15-827 Security and Cryptography
Fall 2000 -  15-451 Algorithms

Etc.

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The contents of this page have not been reviewed or approved by the University of Minnesota.