While not all of these digital assets are considered securities — regulators have said it depends on the specifics of each ICO — many meet the definition of a security and therefore are subject to U.S. securities laws. Already this year, 271 of these offerings have appeared, according to Coindesk. That's on top of more than 340 in 2017. In the last several years, investors have poured more than $12 billion into ICOs. However, the SEC says no ICOs have been registered to date.

Rather, the SEC's Cyber Unit — which has only been around since last September — has brought several fraud cases against operators of ICO offerings. Just this week, the agency announced that it has obtained a court order to shut down an alleged ICO scam that pulled in $21 million in investor money. In total, the SEC alleges $600 million has been raised in fraudulent schemes.

State securities regulators also have been busy. During the first three weeks of May alone, the North American Securities Administrators Association's "Operation Cryptosweep" resulted in nearly 70 inquiries and investigations and 35 pending or completed enforcement actions related to ICOs or cryptocurrencies. Additionally, other investigations into potentially fraudulent conduct are under way, and that's on top of more than a dozen enforcement actions previously undertaken by state regulators.

Even if a particular ICO is held with good intentions, there's no way of ensuring you'll ever see a return on your money. In fact, as is the case with any investment, you could lose all of it. Worse, you face the risk of criminals being behind the ICO and absconding with your money. And if the perpetrators are located overseas, the task of tracking down your investment could be impossible.

"The currency might be virtual, but the pain is real," Schock said. Both federal and state securities regulators have been engaged in public outreach to warn investors about the risks associated with ICOs and cryptocurrencies. The SEC even created its own bogus website to show investors what an ICO scam could look like.

Here are some of the big red flags to watch for.

Generally speaking, investing comes with no promises. So if you're looking at an ICO that is pledging a certain return on your investment, you probably should walk away. "There are no guarantees when it comes to investing,"

Schock said. "A guaranteed return is a major red flag."

If you're invited to use your credit card to buy into the ICO, be very wary. Most licensed and registered investment firms don't let their clients use credit cards to buy investments or fund an account. Remember, too, credit card debt typically comes with interest charges if you can't pay off the balance immediately. So that investment could cost you more than anticipated. "If you don't have the money to buy it outright, you certainly can't afford to go into debt for it," Schock said.

Often, scammers will use high-pressure tactics to create a sense of urgency in the deal."Anything that pushes you to take action now, or discounts that disappear or countdown clocks … those are red flags of fraud," Schock said.