The past few years have seen an explosion of online virtual currencies, the oldest and most popular of which is Bitcoin. Unlike traditional mediums of exchange such as dollars, pounds and yen, Bitcoins are linked to no one nation, are not regulated by a central bank and transactions that use them are not processed by an intermediary financial institution. Because there is no intermediary, purchases made with Bitcoins are more or less as anonymous as those made with cash. The total market cap of these virtual currencies is in the billions, with Bitcoin claiming the lion’s share at $7.3 billion. With numbers like this, it’s no wonder that these currencies have attracted significant attention, both from investors like the Winklevoss twins—who currently hold the largest number of Bitcoins—to regulatory agencies like FinCEN (Financial Crimes Enforcement Network) and, most recently, the Internal Revenue Service (IRS). To help you get a better handle on the virtual currency, here are five things you should know about Bitcoin:

1. Bitcoins are generated through a process called “mining.” In order to create new Bitcoins, a computer equipped with a special type of mining software must receive and solve a complicated math problem—the kind that makes even a PC sweat. The first machine to solve the problem scores the Bitcoin. Thereafter, subsequent problems become more complicated, requiring even more processing power in order to earn the next Bitcoin. That means that the more Bitcoins there are in circulation, the more difficult it becomes to mine new ones. All told, the network is designed to produce a finite number of Bitcoins—21 million. Currently, there are about 12.1 million in circulation.

2. You probably cannot mine Bitcoins yourself anymore. Because they’ve been around since 2009, the math problems required to generate new Bitcoins have become so computationally complex that miners have found it easier to combine their efforts into networks that distribute the fruits of their labor among their members. And it’s not done with your standard PC either: Miners tend to have dedicated specialized machines that are designed to do nothing but mine Bitcoins. This is a very energy-intensive process, and people might find that the gains they make from mining Bitcoins can still be outweighed by their electric bills—it requires that much energy. Consequently, rooms where mining computers are placed tend to also be uncomfortably hot, though according to geek.com, one person came up with an interesting work-around to that problem: He submerged what is essentially a supercomputer in liquid nitrogen.

3. No one knows who invented them. Bitcoin has its roots in a 2008 academic paper that outlined how digital currency might work. The author of this paper is listed as Satoshi Nakamoto, but his actual identity remains unknown, as even the people who worked on the original Bitcoin program have never seen Nakamoto in the flesh. In March, Newsweek claimed to have identified Nakamoto, but it was soon revealed that the magazine had simply found a man who happened to share the same name. Still, while the original inventor, as well as the original investors, remains unknown, he is at the same time fabulously wealthy: Nakamoto is estimated to hold approximately 1 million Bitcoins.

4. Bitcoin is both completely anonymous and completely public. When you make a transaction using a Bitcoin, the entire network knows it. Those aforementioned “math problems” are, in actuality, complex cryptographic calculations that track the current and past ownership of every single Bitcoin in existence in order to ensure that no one is copying, forging or otherwise manipulating the Bitcoin process. It would be akin to spending a single dollar bill and having a computer check the dollar’s serial number against every other dollar bill in existence in order to ensure that it’s the only one with that number, as well as check every transaction that that particular dollar bill was involved in since it first ran off the printing press. However, because this confirmation process runs by Bitcoin address—comparable to a bank account number, essentially—and not by name, while all the computers in the network know that a Bitcoin was indeed spent, they do not know by whom (though intermediaries like exchanges might require you to identify yourself). While tracing transactions to specific people isn’t impossible, it’s extremely difficult and generally more trouble than it’s worth.

5. Bitcoin isn’t the only game in town. Since the Bitcoin computer code is publicly available, any technically minded person can create his or her very own digital currency—and some have.  Though Bitcoin was the first on the scene, there has since been an explosion of other online currencies that are similar, with tweaks here and there. For example, while Bitcoin is, for the most part, a deflationary currency, Dogecoin  is explicitly an inflationary one. Other virtual currencies include Ripple, Litecoin and Coinye (formerly called Coinye West, before a threat of legal action from the performer Kanye West forced a name change).