You can think of bitcoin cash as bitcoin's faster and younger sibling. Functionally speaking, it works in much the same way: It's simply a form of digital cash you can use to buy real-world goods and services, such as a cup of coffee.
But it was invented only last year after a number of developers working on regular bitcoin, or "bitcoin core" as some call it, decided they were unhappy with the direction of the main project.
At issue was how quickly and cheaply bitcoin could process transactions.
Bitcoin's rising popularity had strained the platform's capacity - which meant that over time, if you wanted to buy or sell something on the network, you had to pay ever higher fees to have your transaction cleared.
Bitcoin made certain changes in its code to bring down those fees and speed things up, but the people who wound up creating bitcoin cash wanted to go much further. That's how bitcoin cash was born.
If bitcoin cash ultimately becomes the stronger, more capable digital currency, it could spell trouble for bitcoin core (and its sky-high price), according to Ryan Selkis, a bitcoin investor and founder of the publication CoinDesk.
"You have to be long [on bitcoin cash] as a hedge," he wrote in a recent blog post.
ZCash
One of bitcoin's original benefits was the promise of anonymity.
After all, every wallet or account associated with bitcoin is identified simply by a jumble of letters and numbers, not a person's real name.
But soon, law enforcement and academics began demonstrating that, simply by analyzing a particular bitcoin wallet's public transaction history, you could deduce with relative accuracy who the owner could be.
It's similar to the way looking at a cellphone's location records or Web browsing history can give an indication as to who you are.
"The anonymity it offers is kind of brittle, is the way I've described it," said Jim Harper, the executive vice president of the Competitive Enterprise Institute, a Washington think tank.
ZCash has tried to solve that problem by encrypting not only the wallet information, as bitcoin does, but also by encrypting information about individual transactions as well - hiding it so that casual passersby can't try to reverse-engineer who was paying whom, or even how much.
Monero
Monero is a bit like ZCash, but takes the additional step of mixing together the online addresses of senders and recipients with other possible senders and recipients.
In theory, this makes it harder for the true sender or recipient of money in any transaction to be identified; from the outside, you'd know that one of a number of people listed in the transaction were involved, but you wouldn't necessarily be able to tell which one. In that respect, monero promises privacy through obscurity.
Monero has made headlines recently as a haven for criminal transactions.
That's not surprising, given that illicit behavior tends to seek shelter from the watchful eye of law enforcement. But it could also gain traction among those who are simply conscious of their privacy, or distrust mainstream institutions.
,h2>Ripple
Created in 2012, Ripple is unlike some other crypto-assets. Instead of being controlled by a network of computers that otherwise have nothing to do with each other, as in the case of bitcoin, Ripple is managed by a single company based in California that wants to transform how international payments work.
Today, if you wanted to send money to another country, it could take days for the transaction to clear.
But Ripple promises settlement in four seconds, and according to its website, foreign workers living in Japan are already using the platform to send money back home to Thailand.
"I told people about Ripple when it was under US$1 billion dollars that it was a small company solving a big problem," said Lou Kerner, a venture capitalist at the investment firm Crypto Oracle. "I started getting an avalanche of calls at US$40b." Ripple hit a market cap of US$40 billion in August 2013.
Ethereum
Ethereum is probably the most well-known crypto-asset after bitcoin. It's hard to predict specifically how ethereum will be used, but industry analysts say it could theoretically be beneficial for an even wider range of applications than bitcoin. Where bitcoin could disrupt traditional financial institutions by wresting the power to clear transactions away from big banks and governments, some say ethereum could do the same for apps and online services.
A common example used by ethereum supporters is that of a Web app that, in today's world, would be controlled by a single company, such as Google or Facebook. These companies devote their entire existence to developing and maintaining their proprietary search engines or social networks. But with ethereum, there wouldn't be one company managing those apps - it would be all the computers that are connected to the network, working together as a whole to ensure the entire enterprise stays up and running, and operating correctly.
Experts call this idea a "distributed app," because the programming behind the app is collaboratively written and executed. Here's a series of other efforts to explain what ethereum is and why it could be important.
The bottom line
The ongoing frenzy surrounding the price of crypto-assets has some investors raising their eyebrows.
"I just don't know when buying crypto will stop being a good idea. It was a great idea in 2017," wrote Fred Wilson, a co-founder of the venture capital firm Union Square Ventures, in a blog post.
Investing in crypto-assets may prove disastrous for many investors who leap before they look, Kerner said. But, he added, it's the technology behind the price swings that really matter.
"Ninety percent of people have no idea what these companies do - and that's fine," he said. "In the long run, that won't have any impact on how massively disruptive and wealth-generating it is."