Rolling Stone - The Rise and Fall of a Bitcoin Kingpin 5-15min

How a bullied geek forged an empire out of digital currency, and became a suspect in a half-billion-dollar heist ... During his reign, bitcoin, the leading form of virtual currency, rose in value from approximately a quarter to more than $1,200. The Wall Street Journal estimated that at one point Mt. Gox was processing 80 percent of all bitcoin transactions in the world. At its peak, the company traded more than $4 million a month. ... in February 2014, it was discovered that a half-billion dollars worth of bitcoins simply vanished from Karpeles' exchange, leaving customers around the world unable to withdraw their funds. It's the largest online heist in history. (Estimates vary on the exact amount. Many have reported $450 million; Karpeles says it could be as high as $650 million.) Some — including even those who worked closely with Karpeles — suspected it was an inside job. ... Mt. Gox was originally a site McCaleb had made for people to exchange Magic cards (thus the name — Magic: the Gathering Online Exchange, or Mt. Gox for short). But by July 2010, he'd devoted it to bitcoin instead, setting it up as the currency's first online brokerage ... According to Karpeles, the problem stemmed from what's called a "transaction malleability," a software flaw that allowed people on the outside to manipulate the bitcoin transactions and steal money from the exchange. At first, he tells me, he had no idea how much bitcoin was missing, but the deeper he dug, the worse it became