A man in southern China received administrative punishment after he bypassed the country’s strict internet censorship system to watch porn, state media reported on Wednesday.

The man, surnamed Chen, was apprehended by the local police in the city of Jinshi, located in Hunan province. The police said Chen was using an app called Shadowrocket, which allows users to connect to proxy servers using the censorship circumvention tool Shadowsocks, among other protocols.

Virtual private networks (VPNs) are the most common tools used in China to hop the country’s Great Firewall that blocks access to foreign websites and apps. Facebook, Google and several of the world’s top news sites are all blocked in the country. But Chinese authorities introduced new regulations in 2017 that require VPN providers to officially register with the state, which led Apple to purge VPN apps from its iOS App Store in China.

Some circumvention techniques are more advanced – like Shadowsocks. While often referred to as a VPN, Shadowsocks is technically a disguised SOCKS5 proxy specifically designed to get around the Great Firewall.

While VPNs and Shadowsocks encrypt internet traffic, authorities suggested they were still able to figure out what Chen was browsing. Police said Chen’s main crime was accessing pornographic websites, according to the media report, which cites a now-deleted WeChat post from the city’s public security bureau.

Police didn’t say how they discovered Chen’s online activities. But encryption isn’t necessarily enough to protect users depending on where that data is going. Shadowrocket doesn’t provide any servers itself, just the software used to connect to them.

Authorities didn’t say what Chen’s punishment was, but the Jinshi police hinted at what it could be. They said that people using their own channels to access international networks could be fined up to 15,000 yuan (US$2,142). Those that sell the service could even face prison time.

Some people have already been arrested for selling VPN services in China. A man was arrested for it in 2017, where he was sentenced to five and a half years in prison and fined US$76,000. Police said another man, arrested earlier this year, made US$1.6 million from selling VPNs since 2016.