51% Attack on Bitcoin Gold Shows Risk is Real

Investing.com - A hacking attack on Bitcoin Gold reported last month shows that a so-called 51% attack, a menacing scenario for any cryptocurrency, is no longer just a theoretical risk.A 51% attack happens when hackers gain control of more than half of the mining power on a cryptocurrency network, allowing them to tamper with the blockchain ledger where transactions are recorded.A single digital coin can even be spent more than once, in what’s called a double spend.It is estimated that around $18 million worth of Bitcoin Gold was stolen in the attack, which targeted multiple exchanges.At least three other virtual currencies have suffered 51% attacks in the last two months, including Verge and Monacoin.While the possibility of a 51% attack is nothing new, the chance of attacks occurring had been considered highly unlikely as more and more people joined cryptocurrency networks, making it harder to get control of over half a network.A 51% attack is unlikely to ever hit bitcoin because of the large size of its blockchain, but cryptocurrencies with small networks are vulnerable.