Everything you need to know about Bitcoin

LOS ANGELES -- Bitcoin, the world's most popular virtual currency, isn't like the quarters and bills that you might be used to. The currency is powered instead by lines of computer code that are digitally signed each time they are traded.

Bitcoin isn't tied to a central bank or government, which allows users to spend anonymously. That has proven to be controversial, with some critics saying the currency could be used for money laundering and other illicit activities.

Proponents, however, point out that the currency could prove useful in times of crisis should traditional currency collapse.

The currency has been traced back to a 2008 paper authored by a person or entity known (likely pseudonymously) as Satoshi Nakamoto. While Bitcoin has grown in popularity over the last decade, recent volatility in value has left some experts wondering if Bitcoin is a bubble or a viable, long-term currency.

On Dec. 7, Bitcoin surged above $19,000, dropped back below $16,000, and then see-sawed before settling in just above $17,000.

Major banks took notice, with three of the biggest saying they will either limit or not allow their clients access to the futures when trading begins on the Chicago Board Options Exchange.

The price of Bitcoin fell back the next day, dropping to $15,431.39, according to large Bitcoin exchange Coinbase. At the start of 2017, one bitcoin was worth less than $1,000.

"It would be as if you went to the grocery store to buy something and the value of the dollar in your pocket moved by 50 percent from the time you left your house to buying your groceries," Financial Times capital markets editor Miles Johnson said of the currency's swings.

The Associated Press contributed to this report.