The U.S. Treasury’s Financial Crimes Enforcement Network (FinCEN) has proposed a new anti-money laundering (AML) rule aimed at peeling back the anonymity allowed by certain types of cryptocurrency transactions.

Issued Friday, FinCEN’s proposed rule would require financial institutions like banks and credit unions, as well as “money services businesses” like FinTechs, “to submit reports, keep records, and verify the identity of customers in relation to transactions” related to virtual currency or digital assets held in digital wallets not hosted by a financial institution, known as “unhosted” wallets.

Virtual currencies like Bitcoin or Ethereum can be deposited in these unhosted wallets, funds that are harder for law enforcement to track.

The rule would require banks and FinTechs to report certain types of customer information to FinCEN on any transaction of cryptocurrency worth over $10,000 made on their platforms involving an unhosted wallet. The reporting would have to be done within 15 days, according to the proposed rule. Banks and FinTechs would also be required to keep records for any such transaction over $3,000 and provide that information to law enforcement upon request.

The transaction amounts of $3,000 and $10,000 match up with other AML reporting requirements placed on financial institutions by the Bank Secrecy Act.

“This rule addresses substantial national security concerns in the convertible virtual currency (CVC) market, and aims to close the gaps that malign actors seek to exploit in the recordkeeping and reporting regime,” said Treasury Secretary Steven Mnuchin in a press release. “The rule, which applies to financial institutions and is consistent with existing requirements, is intended to protect national security, assist law enforcement, and increase transparency while minimizing impact on responsible innovation.”

Among the information banks and FinTechs would have to collect on transactions with unhosted wallets are the type of cryptocurrency used; the time of the transaction; the assessed value of the transaction in U.S. dollars; any payment instructions received by the financial institution’s customer; any form relating to the transaction; the name and physical address of “each counterparty” to the financial institution’s customer; and any other information that “uniquely identifies the transaction, the accounts, and, to the extent reasonably available, the parties involved.”

Comments on the rule should be submitted to FinCEN within 15 days of its posting in the Federal Register—an unusually short feedback period. Similar rule proposals often have reporting periods of three months or more.

Coinbase, a digital currency exchange based in San Francisco, will challenge the proposed rule, company CEO Brian Armstrong said Saturday via Twitter.

Senator-elect Cynthia Lummis (R-Wyo.) called the proposed rule “a solution in search of a problem” and criticized the process as non-transparent and hasty.

A hallmark feature of digital assets like Bitcoin, she said Friday via Twitter, “is the ability to conduct transactions w/out an intermediary. This promotes financial inclusion and freedom.”

Earlier this month, Congress passed a defense spending bill that includes AML provisions that attempt to pull back the veil on who controls foreign-owned companies and establish a program that provides financial incentives to whistleblowers who uncover violations of the Bank Secrecy Act. President Donald Trump, however, has threatened to veto the bill because of his opposition to several unrelated provisions.