Blockchain seems very safe, but researchers continue to prove that this statement is not true for the thousands of cryptocurrencies, based on this technology.
Husam Abboud (Husam Abboud), cryptocurrency analyst at FECAP University in Brazil, proved that for carrying out a network attack on Ethereum Classic (ETC) will need only $ 1.5 million, with a market capitalization over $ 2 billion. If you have 55 million you can even bankrupt the currency, leaving a profit of 1 billion.
Proof-of-work blackany especially vulnerable to attacks. The researcher notes that any miner that has at least 2.5% heartrate Ethereum (ETH), may just switch to a Classic mining Ethereum and control more than 51 percent of Ethereum Classic. The amount required to fulfill the so-called “Attack 51%” on the network ETC is 525 ETH (318 000 USD).
Husam Abboud has calculated the cost of the execution of the Attack 51% on Bitcoin Cash, which amounted to 250 BTC per day (2 million USD), Bitcoin and Gold — 26 BTC ($200,000 US). Attacks can last as long as the developers of the cryptocurrency will not make code changes, or until the price becomes so low that to support the attack would be unprofitable.
Abboud notes that the Creator of Bitcoin, Satoshi Nakamoto, developed the consensus Protocol assuming that the miners will not carry out such attacks. According to Satoshi, Attack 51% will reduce the market value of the cryptocurrency, will make it unprofitable for them. But nine years later, it seems, is not so — the current cost of large cryptocurrency is a good way to earn even on the decline.
Concern about the security of cryptocurrencies is growing, given the five attacks in the last two months — Verge , Electroneum, Bitcoin Gold (twice) and Monacoin.
The developers of Bitcoin Jameson Lopp and Peter Todd has previously noted that hardforce larger blockchains lead to the fact that the cryptocurrency will be attacked in this way.
According to experts, there are many solutions to the problem of 51%. These include the transition to proof-of-stake Protocol, increasing the number of required confirmations or upgrading the hashing algorithm. Cryptocurrency with billions in market capitalization can afford to invest a little money in the safety of their network.