Often advertised as a safe place to invest and speculate, blockchain-based cryptocurrency exchanges present a tantalizing opportunity to hackers. As an increasing number of mega-hacks are revealed, even the largest platforms such as Bitcoin and Coinbase acknowledge some risk. Companies specializing in thwarting sophisticated digital thieves propose solutions such as network kill switches and eliminating smart-contract bugs. Regardless, billions of dollars per year disappear into cyberspace, without a chance of recovery. This is a must-read article for anyone considering trading on a cryptocurrency platform.