The app allows end-to-end encrypted messaging, meaning that no malicious individuals or government surveillance would be able to see the contents of the messages without access to specific digital keys.
Signal had its website blocked sometime after 5 March and on or before 15 March, according to GreatFire – a group that monitors internet censorship in the country.
The app apparently remains available in Apple’s App Store in China although it is unclear for how long that will remain the case; Apple and Google’s App Stores vary based on geography, and it is possible that the Chinese government could push the smartphone giant to pull the app.
While The Independent was not able to test the issue, CNBC reports that they tested Signal on three different devices and messages did not go through. The app remains working, however, when users enable a VPN that uses servers outside of China.
Techcrunch reports that Signal has over 500,000 installations in China, and recently crossed 100 million downloads globally on both iOS and Android.
WeChat, an app similar to WhatsApp but with multiple extra social media functions and payment processing, is the main chatting app in China, and as such the backlash against WhatsApp – which is blocked in the country – was likely not noticed as prominently.
Signal did not immediately respond to a request for comment from The Independent. The Cyberspace Administration of China could not immediately be reached for comment.