Ethereum closed a big security hole with its energy-saving update

Ethereum, the world’s second-largest cryptocurrency, made major changes to its structure last year to reduce its energy usage. Security experts say the update also unwittingly sidestepped a serious security flaw that allows hackers to steal funds. However, at least one of his cryptocurrencies, which he copied code and “forked” from Ethereum, is still at risk.

Ethereum relied on “proof of work” to secure the network, much like Bitcoin does today. In other words, computers were performing a huge number of calculations to “mine” new currencies.