Patrick (Pak Kong) Tsang

Patrick is a 4th year PhD candidate in the Department of Computer Science at Dartmouth College. His research interests include Computer and Network Security, Privacy-Enhancing Technologies, Applied Cryptography and Trusted Computing. His academic advisor is Prof. Sean Smith.

He obtained both of his Bachelor of Engineering degree (with first class honors) and Master of Philosophy degree in the Information Engineering program from the Department of Information Engineering at the Chinese University of Hong Kong.

Contact

• Email: patrick at cs dot dartmouth dot edu
• Office: Rm 063, Sudikoff Lab
• Phone: 603-646-8715

Educational Activities

• Summer Robotics and Security Program at Dartmouth College, Summer 2008
  • Lead instructor in Camp I: "Make & Break Cryptographic Security"
  • Reported in Dartmouth News, July 16, 2008, and ISTS Newsletter, vol. 6, no. 1, Summer/Fall 2008
  • Camp material available soon
• Secure Information Systems Mentoring and Training (SISMAT), 2008
  • Instructor
• Women In Science Project (WISP), 2008
  • Mentor in project: "SUPERS: A Smart, Usable and Privacy-Enhancing Reputation System for eBay"
  • Co-mentor in project: "Social Circles: Tackling Privacy in Social Networks"
    • Resulted in a poster abstract at SOUPS '08
• Summer Robotics Program for the Upper Valley Youth, 2007
  • Instructor in the Cybersecurity Camp
  • Reported in ISTS Newsletter, vol. 4, no. 2, Fall 2007
  • Camp materials
• ISTS Cryptography Workshop 2006
  • Organizer and Instructor
  • Workshop materials

Professional Activities

• Financial Cryptography and Data Security, Thirteenth International Conference (FC '09)
  • Program committee member
• Applied Cryptography and Information Security 2006 (ACIS '06)
  • General Co-Chair
  • Superseded by ProvSec.

Publications

Refereed Conference Papers

(Jump to year 2008, 2007, 2006, 2005, 2004)

2009

C-17. DEAMON: Engergy-efficient Sensor Monitoring

• Minho Shin, Patrick P. Tsang, Cory Cornelius and David Kotz.
• In the 6th IEEE Communications Society Conference on Sensor, Mesh and Ad Hoc Communications and Networks (SECON 2009).
• To Appear.
• Acceptance rate: ~19%.

C-16. Dynamic Universal Accumulators for DDH Groups and Their Application to Attribute-Based Anonymous Credential Systems

• Man Ho Au, Patrick P. Tsang, Willy Susilo and Yi Mu.
• In the Cryptographers' Track at the RSA Conference 2009 (CT-RSA 2009).
• To Appear.
• Acceptance rate: ~33%.

2008

C-15. PEREA: Towards Practical TTP-Free Revocation in Anonymous Authentication

• Patrick P. Tsang, Man Ho Au, Apu Kapadia and Sean W. Smith.
• In Proceedings of the 15th ACM Conference on Computer and Communication Security (ACM CCS '08),
• Alexandria, VA, USA, Oct 27-31, 2008.
• pp. 333-344. ACM, 2008.
• Acceptance rate: ~18%. Download: ACM, local copy. Cite: bibtex.

C-14. YASIR: A Low-Latency, High-Integrity Security Retrofit for Legacy SCADA Systems

• Patrick P. Tsang and Sean W. Smith.
• In Proceedings of The IFIP TC-11 23rd International Information Security Conference, IFIP 20th World Computer Congress (IFIP SEC '08),
• Milan, Italy, September 7-10, 2008.
• IFIP 278, pp. 445-459. Springer, 2008.
• Acceptance rate: ~29%. Download: Springer, local copy. Cite: bibtex.
• Note: A preliminary version of this paper appeared as Dartmouth Computer Science Tech Report TR2007-603. An extended version of this paper is available as Dartmouth Computer Science Tech Report TR2008-617.

C-13. PPAA: Peer-to-Peer Anonymous Authentication

• Patrick P. Tsang and Sean W. Smith
• In Applied Cryptography and Network Security, 6th International Conference (ACNS '08)
• New York, NY, USA, June 3-6, 2008
• LNCS 5037, pp. 55-74. Springer-Verlag, 2008
• Acceptance rate: ~23%. Download: Springer, local copy. Cite: bibtex.
• Note: An extended version of this paper is available as Dartmouth Computer Science Tech Report TR2007-615.

C-12. Combating Spam and Denial-of-Service Attacks with Trusted Puzzle Solvers

• Patrick P. Tsang and Sean W. Smith
• In Information Security Practice and Experience, Forth International Conference (ISPEC '08)
• Sydney, Australia, Apr 21-23, 2008
• LNCS 4991, pp. 188-202. Springer-Verlag, 2008
• Acceptance rate: ~31%. Download: Springer, local copy. Cite: bibtex.

C-11. Secure Cryptographic Precomputation with Insecure Memory

• Patrick P. Tsang and Sean W. Smith
• In Information Security Practice and Experience, Forth International Conference (ISPEC '08)
• Sydney, Australia, Apr 21-23, 2008
• LNCS 4991, pp. 146-160. Springer-Verlag, 2008.
• Acceptance rate: ~31%. Download: Springer, local copy. Cite: bibtex.
• Note: A preliminary version of this paper appeared as Dartmouth Computer Science Tech Report TR2007-590.

2007

C-10. Blacklistable Anonymous Credentials: Blocking Misbehaving Users Without TTPs

• Patrick P. Tsang, Man Ho Au, Apu Kapadia and Sean W. Smith.
• In Proceedings of the 14th ACM Conference on Computer and Communication Security (ACM CCS '07),
• Alexandria, VA, USA, Oct 29-Nov 2, 2007.
• Acceptance rate: ~18%. Download: ACM, local copy. Cite: bibtex.
• Note: An extended version of this paper is available as Dartmouth Computer Science Tech Report TR2007-601. Further follow-up work is reported in TR2007-635.
• Media coverage:
  • Cara Garretson. 12 spam research projects that might make a difference -- Image spam, phishing hot topics in the research community. In Network World. 11/20/2007.

C-9. Batch Pairing Delegation

• Patrick P. Tsang, Sherman S.M. Chow and Sean W. Smith.
• In Advances in Information and Computer Security, 2nd International Workshop on Security (IWSEC '07),
• Nara, Japan, Oct 29-31, 2007.
• LNCS 4752, pp. 74-90. Springer-Verlag, 2007.
• Acceptance rate: ~27%. Download: Springer, local copy. Cite: bibtex.

C-8. Nymble: Anonymous IP-Address Blocking

• Peter C. Johnson, Apu Kapadia, Patrick P. Tsang and Sean W. Smith.
• In Privacy Enhancing Technologies, 7th International Symposium (PET '07),
• Ottawa, Canada, Jun 20-22, 2007.
• LNCS 4776, pp. 113-133. Springer-Verlag, 2007.
• Acceptance rate: ~20%. Download: Springer, local copy. Cite: bibtex.
• Note: Further follow-up work is reported in Dartmouth Computer Science Tech Report TR2008-637. Check out our website for an open-source implementation.
• Media coverage:
  • Dennis Fisher. Tor network 'bridges' help evade blockers. In SearchSecurity.com, 12 Mar 2008.
  • tshb. Podcast Episode 1. In Cryptocracy. February 4th, 2008.

C-7. Attribute-Based Publishing with Hidden Credentials and Hidden Policies

• Apu Kapadia, Patrick P. Tsang and Sean W. Smith.
• In the 14th Annual Network & Distributed System Security Symposium (NDSS '07),
• San Diego, CA, USA, Feb 28-Mar 2, 2007.
• Acceptance rate ~ 15%. Download: ISOC, local copy. Cite: bibtex.

2006

C-6. Short Linkable Ring Signature Revisited

• Man Ho Au, Sherman S.M. Chow and Willy Susilo and Patrick P. Tsang.
• In Public Key Infrastructure, Third European PKI Workshop: Theory and Practice (EuroPKI 2006),
• Turin, Italy, Jun 19-20, 2006.
• LNCS 4043, pp. 101-115. Springer-Verlag, 2006.
• Acceptance rate: ~36%. Download: Springer, local copy. Cite: bibtex.

2005

C-5. Universal Custodian-Hiding Verifiable Encryption for Discrete Logarithms

• Joseph K. Liu, Patrick P. Tsang, Duncan S. Wong and Robert W. Zhu.
• In Information Security and Cryptology - ICISC 2005, 8th International Conference (ICISC '05),
• Seoul, Korea, Dec 1-2, 2005.
• LNCS 3935, pp. 389-409. Springer-Verlag, 2006.
• Acceptance rate: ~18%. Download: Springer, local copy. Cite: bibtex.

C-4. Efficient Verifiable Ring Encryption for Ad hoc Groups

• Joseph K. Liu, Patrick P. Tsang and Duncan S. Wong.
• In Security and Privacy in Ad-hoc and Sensor Networks, Second European Workshop (ESAS '05),
• Visegrad, Hungary, Jul 13-14, 2005.
• LNCS 3813, pp. 1-13. Springer-Verlag, 2005.
• Acceptance rate: ~33%. Download: Springer, local copy. Cite: bibtex.

C-3. Recoverable and Untraceable E-cash

• Joseph K. Liu, Patrick P. Tsang and Duncan S. Wong.
• In Public Key Infrastructure, Second European PKI Workshop: Research and Applications (EuroPKI '05),
• Canterbury, UK, Jun 30-Jul 1, 2005.
• LNCS 3813, pp. 1-13. Springer-Verlag, 2005.
• Acceptance rate: ~43%. Download: Springer, local copy. Cite: bibtex.

C-2. Short Linkable Ring Signatures for E-Voting, E-Cash and Attestation

• Patrick P. Tsang and Victor K. Wei.
• In Information Security Practice and Experience, First International Conference (ISPEC '05),
• Singapore, Apr 11-14, 2005, Proceedings.
• LNCS 3439, pp. 48-60. Springer-Verlag, 2005.
• Acceptance rate: ~33%. Download: Springer, local copy. Cite: bibtex.

2004

C-1. Separable Linkable Threshold Ring Signatures

• Patrick P. Tsang, Victor K. Wei, Tony K. Chan, Man Ho Au, Joseph K. Liu, and Duncan S. Wong.
• In Progress in Cryptology - INDOCRYPT 2004, 5th International Conference on Cryptology in India (INDOCRYPT '04),
• Chennai, India, December 20-22, 2004.
• LNCS 3348, pp. 384-398. Springer-Verlag, 2004.
• Acceptance rate: ~17%. Download: Springer, local copy. Cite: bibtex.

Journal Papers

J-2. Nymble: Blocking Misbehaving Users in Anonymizing Networks

• Patrick P. Tsang, Apu Kapadia, Cory Cornelius and Sean W. Smith.
• Currently under review
• An extended version is available as Dartmouth Computer Science Tech Report TR2008-637.

J-1. BLAC: Revoking Repeatedly Misbehaving Anonymous Users Without Relying on TTPs

• Patrick P. Tsang, Man Ho Au, Apu Kapadia and Sean W. Smith.
• Currently under review
• Available as Dartmouth Computer Science Tech Report TR2008-635.

Technical Reports

T-10. Dynamic Universal Accumulators for DDH Groups and Their Application to Attribute-Based Anonymous Credential Systems

• Man Ho Au, Patrick P. Tsang, Willy Susilo and Yi Mu.
• Technical Report 2009-643, Department of Computer Secience, Dartmouth College, Apr 2009.
• Download: Dartmouth. Cite: bibtex
• Note: This report is the extended version of the paper appeared in CT-RSA '09 under the same title.

T-9. Authenticated Streamwise On-line Encryption

• Patrick P. Tsang, Rouslan V. Solomakhin and Sean W. Smith.
• Technical Report 2009-640, Department of Computer Science, Dartmouth College, Mar 2009.
• Download: Dartmouth. Cite: bibtex

T-8. Nymble: Blocking Misbehaving Users in Anonymizing Networks

• Patrick P. Tsang, Apu Kapadia, Cory Cornelius and Sean W. Smith.
• Technical Report 2008-637, Department of Computer Science, Dartmouth College, Dec 2008.
• Download: Dartmouth. Cite: bibtex.
• Note: Nymble first appeared as a PET '07 paper. This tech report presents a significantly improved construction and a complete rewrite and evaluation of our (open-source) implementation.

T-7. BLAC: Revoking Repeatedly Misbehaving Anonymous Users Without Relying on TTPs

• Patrick P. Tsang, Man Ho Au, Apu Kapadia and Sean W. Smith.
• Technical Report 2008-635, Department of Computer Science, Dartmouth College, Oct 2008.
• Download: Dartmouth. Cite: bibtex.
• Note: This tech report extends our work priorly published as a CCS '07 paper and another tech report.

T-6. YASIR: A Low-Latency, High-Integrity Security Retrofit for Legacy SCADA Systems (Extended Version)

• Patrick P. Tsang and Sean W. Smith.
• Technical Report 2008-617, Department of Computer Science, Dartmouth College, Apr 2008.
• Download: Dartmouth. Cite: bibtex.
• Note: This tech report is an extended version of the paper to appear in IFIP SEC '08 under the same title.

T-5. PPAA: Peer-to-Peer Anonymous Authentication (Extended Version)

• Patrick P. Tsang and Sean W. Smith.
• Technical Report 2007-615, Department of Computer Science, Dartmouth College, Apr 2008.
• Download: Dartmouth. Cite: bibtex.
• Note: This tech report is an extended version of the paper to appear in ACNS '08 under the same title.

T-4. YASIR: A Low-Latency, High-Integrity Security Retrofit for Legacy SCADA Systems

• Patrick P. Tsang and Sean W. Smith.
• Technical Report 2007-603, Department of Computer Science, Dartmouth College, Sep 2007.
• Download: Dartmouth. Cite: bibtex.
• Note: This tech report is a preliminary version of the paper to appear in IFIP SEC '08 under the same title.

T-3. Blacklistable Anonymous Credentials: Blocking Misbehaving Users without TTPs (Extended Version)

• Patrick P. Tsang, Man Ho Au, Apu Kapadia and Sean W. Smith.
• Technical Report 2007-601, Department of Computer Science, Dartmouth College, Sep 2007.
• Download: Dartmouth. Cite: bibtex.
• Note: This tech report is an extended version of the paper appeared in CCS '07 under the same title.

T-2. Secure Cryptographic Precomputation with Insecure Memory

• Patrick P. Tsang and Sean W. Smith.
• Technical Report 2007-590, Department of ComputerScience, Dartmouth College, Jul 2007.
• Download: Dartmouth. Cite: bibtex.
• Note: This tech report is a preliminary versionof the paper to appear in ISPEC '08 under the same title.

T-1. A Suite of ID-Based Threshold Ring Signatures with Different Levels of Anonymity

• Man Ho Au, Joseph K. Liu, Patrick P. Tsang and Duncan S. Wong.
• In Cryptology ePrint Archive, Report 2005/326, Sep 2005.
• Download: ePrint. Cite: bibtex.

Refereed Work-In-Progress Papers, Posters and Abstracts

W-3. Social Circles: Tackling Privacy in Social Networks (Poster Abstract)

• Fabeah Adu-Oppong, Casey K. Gardiner, Apu Kapdia and Patrick P. Tsang.
• In the Fourth Symposium on Usable Privacy and Security (SOUPS '08),
• Pittsburgh, PA, USA, July 23-25, 2008.

W-2. SenseRight: Reliable People-centric Sensing with Unreliable Participants (Poster)

• Minho Shin, Cory Cornelius, Daniel Peebles, Apu Kapadia, Patrick Tsang and David Kotz.
• In the 6th International Conference on Mobile Systems, Applications, and Services (MobiSys '08),
• Breckenridge, Colorado, USA, Jun 17-20, 2008.

W-1. Anonymous IP-Address Blocking in Tor with Trusted Computing (Work-in-Progress)

• Patrick P. Tsang, Apu Kapadia and Sean W. Smith.
• In the Second Workshop on Advances in Trusted Computing (WATC '06 Fall),
• Tokyo, Japan, Nov 30-Dec 1, 2006.
• Note: Superseded by the PET '07 paper "Nymble: Anonymous IP-address Blocking".

Magazine Articles

M-1. When Cryptographers Turn Lead into Gold

• Patrick P. Tsang.
• In IEEE Security and Privacy (IEEE S&P),
• vol. 5, no. 2, pp. 76-79, Mar/Apr, 2007.
• Download: IEEE, local copy. Cite: bibitex

Dissertations

D-1. Cryptography in Privacy-Preserving Applications

• Patrick P. Tsang.
• M. Phil. Thesis, Department of Information Engineering, Chinese University of Hong Kong, 2005.
• Download: local copy.

Courses

I've taken

• CS185 Algorithmic Game Theory, Spring 2007. Lecturer: Lisa K. Fleischer.
• CS185 Concurrent Algorithms, Fall 2006. (High Pass.) Lecturer: Prasad Jayanti.
• CS109 Theory of Computation, Spring 2006. (High Pass.) Lecturer: Peter Winkler.
• CS118 Programming Languages, Spring 2006. (High Pass.) Lecturers: William M. McKeeman and M. Douglas McIlroy.
• CS105 Data Structures and Algorithms, Winter 2006. Lecturer: Rahul Ray.
• CS108 Advanced Operating Systems, Winter 2006. (High Pass.) Lecturer: Sean W. Smith.
• CS107 Computer Architecture, Fall 2005. Lecturer: Vincent Berk.
• CS188 Introduction to Bioinformatics, Fall 2005. (High Pass.) Lecturer: Chris Bailey-Kellogg.

I've TA'ed

• CS108 Advanced Operating Systems, Winter 2007. Lecturer: Sean W. Smith.
• CS4 Concepts in Computing, Summer 2006. Lecturer: Chris Bailey-Kellogg.
• CS38 Security and Privacy, Spring 2006. (High Pass.) Lecturer: Sean W. Smith.
• CS18 Structure and Interpretation of Computer Programs, Fall 2005. (High Pass.) Lecturer: Michael J. Fromberger.

Links

• PHD Comics, xkcd, J. Crap., Dilbert, mcplusplus
• Cipher-Call-for-Papers, IACR Calendar of Events in Cryptology
• ISTS, SRG
• Cryptology Pointers, Free Haven's Selected Papers in Anonymity, Bibliography on Digital Signatures

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