It was, by any reckoning, a huge haul. Between $400 million and $534 million dollars of NEM stolen, depending on whether you go on its value at the time or once the market had reacted to the news. At a press conference on Friday afternoon, the stunned Coincheck team painted forlorn figures as they came to terms with being on the receiving end of the greatest heist of all time. In the inevitable post-mortem, questions have been raised about the security practices of the Japanese exchange.