Reversing the 12 years of records on the Bitcoin blockchain would take an attacker no less than 600 days, even if he controlled the hash rate (or processing power) full of the network.
As time has passed, and with the growth of the blockchain, it is increasingly difficult for an attack to reconfigure the Bitcoin network or reverse its history of mined blocks, processed transactions and issued coins, as shown by data from bitcoin.sipa.be.
In its graph of the historical equivalent of Bitcoin’s proof of work (PoW), the process of mining and validating the chain, this website records a clear increase in that difficulty. In just two years, the number of days that an attack of this type would require has doubled, reflects the graph of this website.
The website explains that the calculation arises from the «ratio of the total proof of work divided by the estimate of the hash rate at that moment. So that’s the amount of time it would take for an attacker with 100% hashrate to rewrite the entire blockchain. “
The miners’ processing power is what determines the probability of finding blocks and mine coins on the Bitcoin network. If someone completely controlled that mining power, they could mine all the remaining coins to be mined in Bitcoin. And even so, it would not be so easy to attack the network, which currently accumulates more than 678,000 blocks.
Distribution of mining power in Bitcoin
In the Bitcoin code there are various mechanisms that control the relationship between the processing power and the blocks that are being mined. The idea is to maintain the probability of finding a block every 10 minutes approximately, so that the greater the processing power accumulated in the network, the greater the difficulty (or complexity) of the mathematical processes that the miner must solve.
Currently, the difficulty is at record levels, above 23.13 T, after the most recent difficulty adjustment, clearly exceeding last year’s high. Meanwhile, the mining power in the network is around 160 EH / s, according to data from statoshi.info.
In addition to how difficult it would be to attack Bitcoin to rewrite its history. , the total processing power of the network remains sufficiently distributed that a single group controls 100%.
The largest pool or group of miners at present is AntPool. And it barely controls just over 15% of the Bitcoin hashrate. Only BTC.com, Poolin, F2Pool and Binance Pool each exceed 10% of the network’s processing power, according to data from BTC.com. This gives an overview of how the decentralization of network power makes it robust and secure against attacks.