We all know what a dollar bill looks like. We know what a penny looks like. But what about a bitcoin?

Cryptocurrencies such as bitcoin, dogecoin and ethereum have risen in popularity in recent years, introducing a host of new terminology and concepts to the public that can be tough to visualize and troubling to understand. A 2017 CNBC poll found that 33 percent of Americans hadn’t seen, read or heard anything about bitcoin. And 44 percent had said they had seen, read or heard “just some” about it.

Yet conversations surrounding cryptocurrencies are becoming increasingly common, especially as ransomware attacks, whose perpetrators demand payments in cryptocurrency, heighten awareness among victimized people, companies and municipalities.

On Wednesday, Aug. 4, a trio of U.S. senators proposed new tax reporting requirements for cryptocurrency transactions. In June, El Salvador became the first country to formally adopt bitcoin as a legal tender in a move that would allow citizens to pay taxes via cryptocurrency. In the United States, the NBA’s Dallas Mavericks and Tesla made announcements this year to accept cryptocurrency for merchandise, although Tesla chief executive Elon Musk later rescinded his comments.

So, what’s actually going on? We’ll answer some basic questions to help increase your familiarity.