Facial recognition is being widely embraced as a security tool -- law enforcement and corporations alike are rolling it out to keep tabs on who's accessing airports, stores, and smartphones. As it turns out, the technology is fallible. Researchers with the artificial-intelligence firm Kneron announced that they were able to fool some facial-recognition systems using a printed mask depicting a different person's face. The researchers, who tested systems across three continents, said they fooled payment tablets run by the Chinese companies Alipay and WeChat, as well as a system at a border checkpoint in China. In Amsterdam, a printed mask fooled facial recognition at a passport-control gate at Schiphol Airport, they said.