Grin, a privacy-focused cryptocurrency built on the Mimblewimble protocol, has suffered a 51% attack on its blockchain.
Grin Network Is Under the 51% Attack!— 2Miners (@pool2miners) November 8, 2020
Payouts are stopped. Please mine at your own risk only because the new blocks could be rejected.@grincouncil @grin_hub @Hotbit_news @Poloniex @kucoincom @gateio_info @CoinBene pic.twitter.com/6seDSRe8Qw
The network reorganization took place at block # 949 474. The intruder generated it on November 7 at 22:38 UTC.
Shortly thereafter, he successfully launched several more attacks in an attempt to carry out double bids.
“The success of the attack is uncertain,” wrote a member of the Grin community in the official chat.
Why Grin is vulnerable to a 51% attack
Grin remains vulnerable to replay attacks as unknown mining pools still account for more than half of the network hashrate.
“More than 50% of the network hashrate is currently outside the known pools. Given these circumstances, it is reasonable to wait for additional transaction confirmations to complete the payment,” the Grin website says.
The developers of the cryptocurrency have notified the traders about the situation and are working with them to prevent hackers from spending the coins obtained as a result of the fork.
According to Crypto51, the estimated cost of performing a 51% attack on Grin per hour is $75 at the time of writing.
Bitcoin industry veteran Emin Gün Sirer believes that it was its own consensus protocol that made the Grin network vulnerable to attacks of this kind.
This whole episode is really sad: Grin has an interesting and worthwhile idea embedded in it. But the fact that it tried to invent its own Bitcoin-clone (Nakamoto) consensus protocol made it vulnerable.— Emin Gün Sirer (@el33th4xor) November 8, 2020
“Projects need to focus on the areas where they innovate and use the best available solutions in areas they don’t work in. Just like you don’t run your own cryptocurrency, don’t run your own hash function and consensus protocol, ”he wrote.
Recall that in August, the Ethereum Classic developers confirmed the division of the blockchain into two chains at block #10,904,146. The depth of the reorganization was 3693 blocks, and the damage was estimated at 807,260 ETC.
Five days later, a second 51% attack occurred, followed by a third. After that, the developers prepared a list of measures to protect the network.
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