What are deepfakes? How and why they work

Deepfakes are fake videos or audio recordings that look and sound just like the real thing. Once the bailiwick of Hollywood special effects studios and intelligence agencies producing propaganda, like the CIA or GCHQ's JTRIG directorate, today anyone can download deepfake software and create convincing fake videos in their spare time.

So far, deepfakes have been limited to amateur hobbyists putting celebrities' faces on porn stars' bodies and making politicians say funny things. However, it would be just as easy to create a deepfake of an emergency alert warning an attack was imminent, or destroy someone's marriage with a fake sex video, or disrupt a close election by dropping a fake video or audio recording of one of the candidates days before voting starts.

This makes a lot of people nervous, so much so that Marco Rubio, the Republican senator from Florida and 2016 presidential candidate, called them the modern equivalent of nuclear weapons. "In the old days," he told an audience in Washington a couple weeks ago, "if you wanted to threaten the United States, you needed 10 aircraft carriers, and nuclear weapons, and long-range missiles. Today, you just need access to our internet system, to our banking system, to our electrical grid and infrastructure, and increasingly, all you need is the ability to produce a very realistic fake video that could undermine our elections, that could throw our country into tremendous crisis internally and weaken us deeply."