The secretive company that might end privacy as we know it

Until recently, Hoan Ton-That’s greatest hit was an app that let people put Donald Trump’s distinctive yellow hair on their own photos.

Then Ton-That did something momentous: He invented a tool that could end your ability to walk down the street anonymously and provided it to hundreds of law enforcement agencies.

His tiny company, Clearview AI, devised a groundbreaking facial recognition app. You take a picture of a person, upload it and get to see public photos of that person along with links to where those photos appeared. The system — whose backbone is a database of more than 3 billion images that Clearview claims to have scraped from Facebook, YouTube, Venmo and millions of other websites — goes far beyond anything ever constructed by the U.S. government or Silicon Valley giants.

Federal and state law enforcement officers said that while they had only limited knowledge of how Clearview works and who is behind it, they had used its app to help solve shoplifting, identity theft, credit card fraud, murder and child sexual exploitation cases.

Until now, technology that readily identifies everyone based on their faces has been taboo because of its radical erosion of privacy.

But without public scrutiny, more than 600 law enforcement agencies have started using Clearview in the past year, according to the company, which declined to provide a list. The computer code underlying its app, analyzed by the New York Times, includes programming language to pair it with augmented reality glasses; users would potentially be able to identify every person they saw.

Clearview has also licensed the app to at least a handful of companies for security purposes.

“The weaponization possibilities of this are endless,” said Eric Goldman, co-director of the High Tech Law...