Sadly, the nearly impossible attack has happened. And not with some obscure little crypto-currency no one has ever heard of, but with Ethereum Classic, one of the premier systems, and the home of that transformative invention, the Smart Contract.
An attacker had somehow gained control of more than half of the network’s computing power and was using it to rewrite the transaction history. That made it possible to spend the same cryptocurrency more than once—known as “double spends.” The attacker was spotted pulling this off to the tune of $1.1 million.
To anyone with a shred of common sense, this is a fatal event. It demonstrates that Blockchain’s security has a fatal flaw, even when running in its optimal environment, with public miners.
Eulogy made by David B. Black