Most people familiar with "face-swapping" know it as an innocuous social media feature. An algorithm captures a person's face and pastes it onto someone else's. The result is rarely seamless and often funny.
But as it grows more sophisticated, that technology has taken a sinister turn: It's now become easier to superimpose the faces of celebrities onto those of actors in pornographic films, resulting in highly-realistic fake videos.
Deepfakes, as the digital form is called, takes its name from the Redditor "deepfakes," the first person known to create these fake porn videos. Celebrities Daisy Ridley, Gal Gadot and Taylor Swift are among deepfakes' early victims.
Samantha Cole, an editor at Motherboard, who first reported on the trend, tells NPR's Scott Simon that the videos are created using a machine-learning algorithm, which is trained by processing hundreds of photos of an individual's face.
"Someone takes a dataset of one person's face — and a lot of pictures of that person's face — and then a video that they want to put it on," Cole says. "And they run a machine-learning algorithm, train it on these two images, and after a few hours, gives you the result, which is, these very realistic, fake porn videos."