When the investigative news site was working on a report last year about Chinese online censorship, it wanted to make sure it would be safe for Chinese readers to access the piece, according to Wired.

Thus began ProPublica’s move to launch a version of itself as a hidden service and become the first major media outlet to use an anonymity shield of untraceable websites in the so-called dark net or dark web. ProPublica is using the Tor network, which hides the IP address of a website and its administrator’s identity.

Wired reported, “Unlike mere SSL encryption, which hides the content of the site a web visitor is accessing, the Tor hidden service would ensure that even the fact that the reader visited ProPublica’s website would be hidden from an eavesdropper or Internet service provider.” 

Mike Tigas, ProPublica’s news applications developer who worked on the Tor hidden service, told Wired,  “Everyone should have the ability to decide what types of metadata they leave behind. We don’t want anyone to know that you came to us or what you read.”

The Wired article provides other details of how security on ProPublica regular website differns from its newly launched, more totally anonymous site. It also explains how another Tor hidden service called SecureDrop is used by ProPublica and other news sites for anonymous tips and leaks.