I received my Ph.D. from the Johns Hopkins University in 2008. I was a member of the Security and Privacy Applied Research (SPAR) lab. SPAR is affiliated with the Computer Science Department and the Information Security Institute (ISI). Before coming to Hopkins I studied Computer Science and Mathematics at Brandeis University.

I am interested in applied computer security. Most of my research has been devoted to studying applications that rely (explicitly or implicitly) on differences in human behavior to achieve some notion of security. Our studies of biometrics and VoIP have shown that these differences are not large enough to offer sufficient security in certain situations.

Having graduated, I am now pursuing similar interests at Google, Inc.

Education

• Ph.D. Computer Science, The Johns Hopkins University, 2008
• M.S.E. Computer Science, The Johns Hopkins University, 2006
• M.S. Security Informatics, The Johns Hopkins University, 2004
• B.S. Computer Science, Mathematics, Brandeis University, 2003

Dissertation

• Robust Techniques for Evaluating Biometric Cryptographic Key Generators
  L. Ballard, Dept. of Computer Science, The Johns Hopkins University, March 2008.
  [abstract]

Publications

• Biometric Key Generation using Pseudo-Signatures
  L. Ballard, J. Chen, D. Lopresti, and F. Monrose. To appear in proceedings of The 11th International Conference on Frontiers in Handwriting Recognition, Montreal, Quebec, CA, August 2008.
• The Practical Subtleties of Biometric Key Generation
  L. Ballard, S. Kamara, and M. K. Reiter. To appear in the proceedings of The 17th Annual USENIX Security Symposium, San Jose, CA, August 2008.
  [abstract]
• Spot me if you can: Uncovering Spoken Phrases in Encrypted VoIP Conversations
  C. V. Wright, L. Ballard, S. Coull, F. Monrose, and G. M. Masson. To appear in the proceedings of The IEEE Symposium on Security and Privacy, Oakland, CA, May 2008.
  [abstract][pdf]
• Forgery Quality and its Implications for Behavioral Biometric Security
  L. Ballard, D. Lopresti, and F. Monrose. In IEEE Transactions on Systems, Man, and Cybernetics---Part B: Cybernetics (Special Edition). Volume 37, Number 5, pp. 1107-1118, October 2007.
  [abstract][pdf]
• Language Identification of Encrypted VoIP Traffic: Alejandra y Roberto or Alice and Bob?
  C. V. Wright, L. Ballard, F. Monrose, and G. M. Masson. In the proceedings of The 16th Annual USENIX Security Symposium, pp. 43-54, Boston, MA, August 2007.
  [abstract][pdf]
• Evaluating Biometric Security (Invited keynote paper)
  D. Lopresti, F. Monrose, and L. Ballard. In the proceedings of the First Korea-Japan Workshop on Pattern Recognition, pp. 15-24, Jeju Island, Korea, November 2006.
  [abstract][pdf.gz]
• Evaluating the Security of Handwriting Biometrics
  L. Ballard, D. Lopresti, and F. Monrose. In the proceedings of The 10th International Workshop on Frontiers in Handwriting Recognition (IWFHR06), pp. 461-466, La Baule, France, October 2006.
  [abstract][pdf]
• Biometric Authentication Revisited: Understanding the Impact of Wolves in Sheep's Clothing
  L. Ballard, F. Monrose, and D. Lopresti. In the proceedings of The 15th Annual USENIX Security Symposium, pp. 29-41, Vancouver, BC, Canada, August 2006.
  [abstract][pdf]
• Achieving Efficient Conjunctive Keyword Searches over Encrypted Data
  L. Ballard, S. Kamara, and F. Monrose. In the Proceedings of the Seventh International Conference on Information and Communications Security (ICICS '05), pp. 414-426, Beijing, China, December 2005.
  [abstract]
• An Extensible Platform for Evaluating Security Protocols
  S. Kamara, D. Davis, L. Ballard, R. Caudy and F. Monrose. In ANSS '05: Proceedings of the 38th Annual Symposium on Simulation, pp. 204-213, San Diego, CA, USA, 2005. IEEE Computer Society.
  [abstract][pdf][code]

Professional Service

• Biometrics Symposium at the Biometrics Consortium Conference (2007, 2008)
• International Conference on Distributed Computing Systems (2008)

• ACM Transactions on Information and Systems Security
• EURASIP Journal on Information Security
• IEEE Transactions on Computers
• IEEE Transactions on Pattern Analysis and Machine Intelligence
• IEEE Transactions on Information Forensics and Security
• Information Processing Letters
• International Journal of Pattern Recognition and Artificial Intelligence

• ACM Workshop on Multimedia and Security
• IEEE Symposium on Security and Privacy
• Information Security Conference
• International Conference on Applied Cryptography and Network Security
• International Conference on Distributed Computing Systems
• International Conference on Document Analysis and Recognition
• ISOC Network and Distributed Systems Security Symposium
• USENIX Security Symposium
• USENIX Workshop on Large-scale Exploits and Emergent Threats
• Workshop on Information Security Applications