Cryptocurrencies  have gained a lot of negative publicity recently, due in large  part to their wildly volatile prices, but also due to reports  of cryptocurrency theft to the value of over US$ 1 billion in 2018  alone. This is particularly alarming for a currency that was touted as  being blockchain-based, and hence super-secure. I have nothing against  cryptocurrencies; I believe they are great in theory, even though they  do have some unresolved issues. But in time, they might evolve to a  point where theory becomes a practical reality.