Over the summer, Google developed a new algorithm that rather grandly promised to eradicate child pornography from the Internet.

That might sound impossible, but it’s already led authorities to make at least one arrest, after the software tracked down a Texas man who was sending pictures of child sex abuse over email.

The software has raised eyebrows among those concerned about privacy, but Google dismissed such fears. The technology is based on a Microsoft innovation called “PhotoDNA” that matches emailed images against a mathematical algorithm to determine whether they involve sexual abuse of minors.

At this point, Google says they’re only using the software to look for anyone distributing child pornography, and no other type of illegal content.