At one point, the Mt. Gox exchange facilitated 80 percent of the world's Bitcoin transactions. That was, at least, until 2014 when someone absconded with hundreds of millions of dollars worth of the digital currency -- as well as an additional $28 million in cash -- from the exchange's accounts. Authorities in Japan have since fingered the site's chief executive, Mark Karpeles, as the caper's culprit. However, as his trial got underway on Thursday, the 32-year old French national declared his innocence, per Reuters.