Mark Zuckerberg was the subject of a viral deepfake video earlier this year The Washington Post / Getty

Fake videos created by artificial intelligence are now so realistic that they are becoming useful.

Israeli tech firm Canny AI is one of several companies cashing in on so-called deepfakes, using the technology to dub videos into different languages. The firm is currently using it to dub advertisements or messages from celebrities for audiences in different countries and plans to use it for television shows and films in the future.

Deepfakes make it easy for people with a bit of technical know-how …