Back in January, news of reversed transactions on the Ethereum Classic (ETC) blockchain (little brother to the main Ethereum blockchain) made headlines and raised concerns about blockchain security. The product of a “51% attack,” these transaction reversals allowed some ETC tokens to be spent twice, a cardinal sin in cryptocurrency called a “double spend,” and … Continue reading (Un)making History: ETC, a 51% Attack and How to Change an Unchangeable Blockchain