The world’s least anonymous social network just got a little more private.

Facebook, which has a controversial policy that mandates that users provide their real names and other personal information, has become the first major social network to launch a “dark Web” version of its site, allowing users of popular anonymity software Tor to hide their location from Facebook and protect their data from online spies, be they of the government or corporate variety.

Digital security experts lauded Facebook’s hidden-site experiment, which allows users to access Facebook via an alternate Tor-enabled .onion URL, as a sign the tech giant was shifting gears on some users’ long-running demands for greater privacy. Once Tor seemed to undermine a basic Facebook premise — that a social network should represent users’ true identities — but it has since come to be viewed as a valuable bridge enabling millions of users to log on in countries where Facebook is banned.

Tor works by bouncing a user’s data across several encrypted nodes — volunteer computers and servers anywhere in the world — before arriving at a website as a request. The data, therefore, appears to be coming from the last node in the chain instead of from the user’s computer. The name is an acronym for “the onion router,” a reference to added layers of encryption this process provides.

Facebook and other major sites, including Twitter and Google, have in recent years adopted SSL encryption, which helps safeguard users’ traffic from local eavesdroppers, like the owner of an Internet cafe with Wi-Fi. Tor goes a critical step further by obscuring a user's Web traffic from even the Internet service provider (ISP), making it almost impossible for other parties — from cyberintelligence units to marketers — to identify and locate that user.

“There’s no reason to let your ISP know when or whether you’re visiting Facebook,” wrote Roger Dingledine, the president and director of the Tor Project, in a post commending Facebook’s move. “If you do choose to tell Facebook something about you, there’s still no reason to let them automatically discover what city you’re in today while you do it.”

Hundreds of thousands of users across the globe are already using Tor to access Facebook, but the “dark” site will add extra layers of encryption on Facebook’s end. It will also address problems Tor users run into when logging into Facebook, which has in some cases blocked their connections because it mistakes the circuitous data routing for a hijacked computer.

“Tor challenges some assumptions of Facebook’s security mechanisms,” wrote Alec Muffett, a Facebook software engineer, in a post announcing the new Tor URL. “For example, its design means that from the perspective of our systems, a person who appears to be connecting from Australia at one moment may the next appear to be in Sweden or Canada. In other contexts such behavior might suggest that a hacked account is being accessed through a botnet, but for Tor, this is normal.”