the Ethereum Classic was attacked. The crypto-Exchange Kraken has temporarily frozen all of the Ethereum-Classic-transactions. Coinbase reported on 13 reorganizations of blocks, in which Double spending occurred, and so a total of 219.500 ETC were issued. The Community is not thrilled.

By Phillip Horch
8. January 2019TeilenFacebookTwitterLinkedInxingemail

Ethereum Classic trying currently to defend unsuccessfully against an attack. Different pages speak of a 51% attack, even if this is denied by the developer teams behind Ethereums small brother. Because Coinbase reported currently using a total of 219.500, ETC., which were double-spent. Stock.

What is a 51 percent attack?

Blockchains have a weak: A Miner with a large enough Hash Rate can change in a limited setting, the history of the Blockchain. A malicious Miner can feed a new Version of the Blockchain in the network. One speaks of a Chain reorganization. This makes it possible, inter alia, a so-called Double-Spending: The attacker can then spend the same Coins twice, once before the Chain reorganization, and once after. More on this in our Tutorial. Both the 51-percent attack, as well as other attack vectors against Mining-based networks can be found in an older article about the security of the Bitcoin network.

Ethereum Classic and the Double Spend

To prevent this Problem, discussed by Satoshi Nakamoto in his Bitcoin White Paper in detail. Currently, the Ethereum clone Ethereum Classic suffers, however, exactly such an attack.

Coinbase, the largest Bitcoin exchange in the United States, reported currently the fact that you have discovered a reorganization of the Blockchain. It managed attacker to organize 13 blocks and thus a total of 219.500 Ethereum Classic (ETC) twice. It is said in the message:

„Coinbase discovered a profound reorganization of the Ethereum Classic Blockchain, which included a Double Spend. In order to protect the customers ‚ funds, we have completed the interactions with the ETC in the Blockchain immediately. After this event, we discovered eight more reorganizations, including double-spending in the amount of 88,500 ETC (about of 460,000 US dollars). Update: After this event, we discovered twelve additional reorganizations, including double-spending in the amount of 219.500 ETC (about 1.1 million US dollars).“

the reorganization of The Ethereum-Classic-Blockchain, so the description of the contents of individual blocks which makes it the attacking miners so possible, the same Coins twice.

Kraken and Coinbase can freeze a

As to the blog post from Coinbase, the exchange is already at 5. January to inconsistencies to the attention of. At that point in time the Team, however, only a reorganization of the blocks. First Double Spends then followed at 6. January. The you can more accurately track.

the crypto-Exchange Kraken has frozen transactions, Ethereum Classic currently. So it says on the home page:

„Because of the 51% attack persists, apparently, we have to set the deposits and withdrawals of ETCs temporarily. We will continue to monitor the Situation, but ETC again online, if we are to believe that this is safe.“

In addition, decided to Kraken, the confirmation for transactions of 120 screw on 500. This followed a recommendation by the Ethereum Classic Community on Twitter:

„We are working together with Slow crap and many others in the crypto-Community. We recommend that Exchanges and Pools, to increase the confirmation times (400-4000+).“

Ethereum Classic in the cross-fire of criticism

With the increase of transaction times, Ethereum hopes to Classic, to prevent the attacks, since the increase in the confirmations of the Blockchain is more secure. The Community is inspired by these processes, however, less: