One of China’s “Big 3” exchanges is demanding its bitcoin users to specify the origins of their funds, Chinese media outlets reported.

According to CNLedger.com, users of Huobi were recently asked to identify where they got their funds, provide bank transfer records of moving funds from a legitimate bank to Huobi and also provide an extensive explanation not only on the transfer, but also where the money is transferred to and how the customer intends to use the digital currency.

“With this step, we expect #bitcoin withdraws from major exchanges become available soon,” the Chinese news outlet tweeted.

Under the new guidelines, bitcoin users need to submit four documents before they can trade with any digital currency exchanges in the Chinese market. The requirements, according to the report, are part of the People’s Bank of China’s (PBoC) new know-your-customer and anti-money laundering systems for cryptocurrency exchanges.