What Is a Deepfake?

In the opening session of his 2020 introductory course on deep learning, Alexander Amini, a PhD student at the Massachusetts Institute of Technology (MIT), invited a famous guest: former US President Barack Obama. "Deep learning is revolutionizing so many fields, from robotics to medicine and everything in between," said Obama, who joined the class by video conference. After speaking a bit more on the virtues of artificial intelligence, Obama made an important revelation: "In fact, this entire speech and video are not real and were created using deep learning and artificial intelligence." Amini's Obama video was, in fact, a deepfake--an AI-doctored video in which the facial movements of an actor are transferred to that of a target. Since first appearing in 2018, deepfake technology has evolved from hobbyist experimentation to an effective and dangerous tool. Deepfakes have been used against celebrities and politicians and have become a threat to the very fabric of truth.