China's Great Firewall, used by the government to regulate access to foreign internet sites, has blocked one of the most popular sources of ethereum blockchain data.
As of Tuesday, etherscan.io, one of the longest-running and most widely used ethereum block explorers, was inaccessible from IP addresses inside mainland China, based on tests performed locally.
The change appears to be recent. According to Greatfire.org, which compiles and monitors a database of sites that are blocked inside China, etherscan.io was still accessible with "no censorship detected" as of Aug. 18, 2019.
But Greatfire.org's scanning record shows etherscan.io has become 100 percent blocked since at least Oct. 30, rendering it inaccessible from inside China unless via a virtual private network (VPN).
This is likely the first known case of a blockchain explorer becoming an internet firewall target and puts etherscan.io in the company of such blocked information and social media sites as Google, Facebook, Twitter, and Reddit.
"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 blockchain investment firm 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 exactly led to the blocking of a blockchain explorer in China. But last year, there were reports that cryptocurrency users encoded censored articles regarding the #Metoo movement and a pharmaceutical scandal in China onto ethereum transactions in a bid to bypass internet censorship.
Internet users had been sharing on WeChat the hash of those transactions using etherscan.io, which even prompted WeChat to later block users from viewing the exact etherscan.io URLs from inside the messaging app. Etherscan.io's site itself remained intact at the time.