Once hailed as unhackable, blockchains are now getting hacked
Early last month, the security team at Coinbase noticed something strange going on in Ethereum Classic, one of the cryptocurrencies people can buy and sell using Coinbaseâ€™s popular exchange platform. Its blockchain, the history of all its transactions, was under attack.
n attacker had somehow gained control of more than half of the networkâ€™s computing power and was using it to rewrite the transaction history. That made it possible to spend the same cryptocurrency more than onceâ€”known as â€śdouble spends.â€ť The attacker was spotted pulling this off to the tune of $1.1 million. Coinbase claims that no currency was actually stolen from any of its accounts. But a second popular exchange, Gate.io, has admitted it wasnâ€™t so lucky, losing around $200,000 to the attacker (who, strangely, returned half of it days later).
Just a year ago, this nightmare scenario was mostly theoretical. But the so-called 51%...
Charles Brett wrote: As noted economist Nouriel Roubini has written: â€śAs for the underlying blockchain technology, there are still massive obstacles standing in its way, even if it has more potential than cryptocurrencies. Chief among them is that it lacks the kind of basic common and universal protocols that made the Internet universally accessible (TCP-IP, HTML, and so forth). More fundamentally, its promise of decentralized transactions with no intermediary authority amounts to an untested, Utopian pipedream. No wonder blockchain is ranked close to the peak of the hype cycle of technologies with inflated expectations....
from "Blockchain disadvantages: 10 possible reasons not to enthuse"đź’°
First off, 51% is an attack not a hack. Second, exchanges have ways to adjust minimum transaction confirmations to almost eliminate any threat from such attacks. A lot of wallets for PoS and other coins have added algorithms and checkpoints to practically eliminate most of the 51% attack vectors also. It's still an ongoing threat but if the coin still matters the ecosystem responds and shuts most attacks down pretty swiftly and with minimal to no loss.