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Luis von Ahn

Associate Professor, School of Computer Science


Luis von Ahn

Cross Cutting Thrusts

Usable Privacy and Security


Luis von Ahn is an Associate Professor in the School of Computer Science. His research interests include novel techniques for utilizing the computational abilities of humans, such as games in which people collectively solve large-scale problems that computers cannot yet solve; human-computer interaction, artificial intelligence, and the difference in computational abilities between humans and computers (e.g.,; theoretical cryptography and security, and computer science theory in general.

I build systems that combine humans and computers to solve large-scale problems that neither can solve alone. I call this Human Computation, but others sometimes call it Crowdsourcing. Some of my past projects include: CAPTCHA, The ESP Game (acquired by Google), GWAP, and reCAPTCHA (acquired by Google).

I'm currently working on Duolingo. (Talk on


Ph.D. in Computer Science, 2005. Carnegie Mellon University. Pittsburgh, PA.
M.S. in Computer Science, May 2003. Duke University, Durham, NC.
B.S. in Mathematics (Summa Cum Laude), May 2000.

Research Projects

Audio CAPTCHAs for Authenticating Human Users

Cross Cutting Thrusts: Usable Privacy and Security
Researcher: Luis von Ahn

The CAPTCHA Project

Researchers: Manuel Blum, Luis von Ahn


"Input-Agreement: A New Mechanism for Collecting Data Using Human Computation Games". Edith Law and Luis von Ahn. ACM Conf. on Human Factors in Computing Systems, CHI 2009. pp 1197-1206.

"Matchin: Eliciting User Preferences with an Online Game". Severin Hacker and Luis von Ahn. ACM Conf. on Human Factors in Computing Systems, CHI 2009. pp 1207-1216.

"General Techniques for Designing Games with a Purpose". Luis von Ahn and Laura Dabbish. Communications of the ACM, August 2008. pp 58-67.

"reCAPTCHA: Human-Based Character Recognition via Web Security Measures". Luis von Ahn, Ben Maurer, Colin McMillen, David Abraham and Manuel Blum. Science, September 12, 2008. pp 1465-1468.

"Games With A Purpose". Luis von Ahn. IEEE Computer Magazine, June 2006. pp 96-98.