Von Ahn developed reCAPTCHA while teaching computer science at Carnegie Mellon University. The omnipresent program generates the squiggly words websites use to confirm users are human. Von Ahn sold it to Google in 2009, and soon after co-founded the language-learning app Duolingo, where he serves as CEO. Luis von Ahn is a young computer scientist working at the intersection of cryptography, artificial intelligence, and natural intelligence to address problems of profound theoretical and practical importance. One line of his work focuses on a subdiscipline of cryptography known as steganography; unlike standard encrypted communications, a steganographic message disguises the fact that it contains a secret. Luis von Ahn was born in Guatemala City, Guatemala in 1978 and received a B.S. (2000) in mathematics from Duke University and a Ph.D. (2005) in computer science from Carnegie Mellon University. He was a postdoctoral fellow (2005-2006) at the Center for Algorithm Adaptation Dissemination and Integration (ALADDIN) at Carnegie Mellon and became an assistant professor in the department of computer science in 2006.