Another victim of 51% attack: ZenCash loses $500K
On June 2, the ZenCash network was robbed via so-called 51%-attack, a hacker attack when a group of miners takes under control over 50% of the network’s hashrate, or computing power. Hackers have stolen over $500,000 in total.
Verge, Bitcoin Gold, ZenCash - who's next? :(
By controlling the majority of the computational power, hackers are able to interfere the process of recording new blocks. For instance, hackers can cheat and cell the same coins multiple times. The vulnerability behind this called double-spending, where a set of coins is spent in more than one transaction. In the ZenCash attack, hackers were able to double spend two large transactions – 13,000 and 6,600 ZEN.
ZenCash is a platform developed for private communications and private transactions. Founded in 2017, ZenCash possesses a Proof of Work consensus algorithm and Equihash mining algorithm that is applied by several other cryptocurrencies. The ZenCash team comments on their blog that
“a 51% attack or double spend is a major risk for all distributed, public blockchains. All Equihash-based networks are exposed to an influx of new Equihash power and therefore the best short-term mitigation strategy is to recommend that all exchanges increase their minimum required confirmations to at least 100.”
The team further reports that is executed migration procedures to rise the difficulty of attacks on the network.
Bitcoin Gold and Verge are other cryptocurrencies that suffered from the 51% attack. The attack on ZenCash is the fourth major 51% attack. 51Crypto, web-service that evaluates approximate costs of 51% attacks, has estimated the costs of ZenCash hack to be roughly $30,000.