Bitcoins are the digital, peer-to-peer currency now accepted as payment in bars from Berlin to London and many other stores. They were first introduced in 2008.

A year later, Norwegian engineer Kristoffer Koch bought about $24 worth on a whim.

For years, Koch's bitcoins sat forgotten in his online account. Then, he started hearing about the increasing value of bitcoins in the media and remembered he'd bought some. One catch — he'd forgotten his password. Luckily, after hours of concentration, it "finally came back to him."

Now, his investment is worth nearly $886,000.

Bitcoin's meteoric rise in value came as a shock to Koch, who first heard about the currency while working on a master’s thesis in electrical engineering.

“I just bought them as a toy investment, just to play around – could I buy something with these? It wasn't a very big thing then.”

As a result of the tremendous increase in value of his bitcoins, Koch recently purchased an apartment in a wealthy area of Oslo. He cashed in just 80 percent of his investment, and he's hanging onto the last 20 percent to see where it goes.

Koch says he's not sure if bitcoins are necessarily the way of the future, but he thinks now that the idea of a decentralized currency is out there, it won't soon be forgotten.

"Everyone can understand how it works and implement something like it," he says. "Or better — improve it."