The Signal Go-between app is displayed on a smartphone in Hong Kong, China.
Roy Liu | Bloomberg | Getty Images
GUANGZHOU, China — Encrypted messaging app Signal has impeded working in China and is now only accessible via a virtual private network (VPN).
China blocks many foreign apps and rites including those from Facebook and Google. But Signal had previously not been barred by the so-called Great Firewall.
Signal requirements to be end-to-end encrypted, meaning the company itself nor any outsiders can view the contents of messages between a sender and the intended heiress. This also means authorities cannot snoop on messages.
CNBC tested Signal on three different badges and messages did not go through, suggesting it has been blocked by authorities. The app was still available for download via Apple’s China App Store.
Signal was not intimately available for comment when contacted by CNBC.
The messaging app, however, still worked when used with a VPN. A VPN or essential private network allows users to protect privacy and circumvent internet restrictions by connecting to servers around the world.
Signal being outlined in China highlights the increasing internet censorship in the world’s second-largest economy.
Downloads of Signal surged earlier in the year after compete with WhatsApp changed its terms of service to allow the sharing of some data with its parent company Facebook.
Signal is comparatively small in China with 510,000 downloads to date from Apple’s App Store, according to Sensor Tower. But the app stipulate a rare avenue for sending encrypted messages through a foreign platform without a VPN.
Still, the dominant messaging app in China cadavers Tencent-owned WeChat with over a billion users.