The head of online investigations for the US government’s tax collection agency is concerned that digital currencies could be used to evade taxes, and is considering new disclosure rules for businesses that use them.

To which we say, well, duh.

While there may be some confusion about the IRS approach (since the Financial Times article on it references PayPal, which is not a digital currency but an online payments processor) it’s clear that there are real issues. Liberty Reserve, the alternative currency exchange shut down by the government for allegedly providing secret financial services to all manner of criminals, could have easily been (and was probably) used for tax fraud.

There’s nothing new under the sun, and digital currencies are no exception. Neal Levin, an attorney who specializes in fraud investigations, says that the two tools Liberty Reserve used to evade financial scrutiny—anonymity and layering transactions through multiple companies—are already embedded in the international financial system. The difference now is merely access and scale.

“The internet has provided perhaps a more streamlined methodology, greater access, and allows the money to get up into those billions of dollars,” he says. “When offshore financial centers first became trendy many, many years ago, you used to have to go to the offshore location, take the money with you, and deposit it in the bank. Now, you don’t have to go to Guernsey or Cayman or BVI and actually speak to someone on the ground or sign papers in person to open up an offshore bank account.”

The internet has shrunk the world, and Liberty Reserve and other digital currencies similarly help bring offshore banking to the masses.

The US typically combats tax evasion through disclosure, as with FATCA, its requirement that non-US banks share the details of their US customers’ accounts. Similarly, US businesses that transmit money are required to adopt know-your-customer policies and monitor large transactions; it is these regulations that led to the closure of bitcoin exchange Mt. Gox’s US subsidiary and its subsequent compliance efforts.

The government’s interest in setting rules for digital currencies may dismay some of their most enthusiastic users, but also represent the path to mainstream use and the opportunity to prove their advantages over physical currency.