Theoretically unbreakable encryption schemes like those underpinning blockchain have proven to be less than impermeable in practice, as users of Coinbase discovered upon losing fortunes. Attackers go after the weakest link in the chain, usually the way in which the algorithm is implemented. Perhaps more ominous, the emergence of a new class of devices called quantum computers threatens to eat the algorithms that underlie crypto for lunch. 

Jerry Lawson and Elizabeth Southerland

The rest of the article discusses the non-technical reasons why cryptocurrency mania must come to and end–possibly very quickly.