The Great Chinese Firewall, used by the authorities to regulate access to foreign websites, blocked etherscan.io, one of the most popular statistics services for the Ethereum network.

According to CoinDesk, as of early December, the portal is not accessible from IP addresses in mainland China. According to the service greatfire.org, blocking has been carried out at least since October 30.

Presumably, this is the first time that a blockchain observer has become a target for Internet censorship in China.

“This is another instance of friction between the decentralized and immutable technology of blockchain and the tightly controlled, centralized government of China,” said Matthew Graham, CEO of Sino Global Capital. “We should expect additional problems like these in the future as blockchain is integrated further into the Chinese economy and daily life.”

It’s not immediately clear what caused etherscan.io to be blocked.

Last year, it was reported that users encoded censored articles in an Ethereum transaction and shared the hashes of these transactions in the WeChat messenger using etherscan.io.

“Some have used this feature to post sensitive messages without the need to worry about the message being blocked or removed, or their identity being exposed,” said Graham. “Anyone with a blockchain explorer like Etherscan can view these messages, so it is not surprising that this website has come in the crosshairs of internet censors.”

The founder of etherscan.io, Matthew Tan, confirmed that the website in China has been blocked “within the last 3 months.” He is also not sure of the exact date and reason for what happened.