casinos and registered sports betting companies. “This segment has exploded in a very short amount of time, and as a decentralized system, it makes it even more difficult to figure out how to go after them,” said Alex Costello, the vice president of government relations at the American Gaming Association, a trade group that lobbies on behalf of U.S. now offer a way to quickly begin gambling, many with few checks on users’ backgrounds.

Dozens of websites operating outside the U.S. Internet casinos that offer users a way to gamble using cryptocurrencies are booming, sidestepping regulations while operating and advertising with near impunity.