Blockchain has a set of rules to help it come out of the very small but complex problems like double spending. Double spending is when owing to the slow nature of the transactions two people spend the same bitcoin at once. And both are validated.
The defensive play of making sure all nodes agree that the bitcoin was spent right does not occur.
Both units of blockchain agree that the money was spent, when the nodes to talk to each other they use the longest chain rule to come out of the mess.
And what happens when the longest chain is muddled or corrupt?
Remember bitcoin’s network is automated in a lot of mathematical ways, the rules which are known could be broken with ease by finding ways around them.
But, then who would go through the tedious task of breaking these rules and attacking the mighty juggernaut of complexity that Bitcoin is.
Is it Feasible to Attack Bitcoin?
Now, obviously, this isn’t an easy or cheap attack to pull off on Bitcoin. If the attacker was to rent mining power from NiceHash, it’s estimated that a one-hour 51% attack would cost ~$230k. But the service does not allow this to happen.
Alternatively, other chains are much cheaper to take over – we’ve seen this play out with other coins in recent months, most notably Bitcoin Gold, Verge, and Monacoin. The reward is higher and security is lesser. The pattern tends to be attackers sending coins to an exchange, cashing out into a more secure cryptocurrency, then propagating their (longer) chain with those coins still in their custody.
Many are concerned that if such an attack were to take place on Bitcoin, it would be conducted through the collusion of mining pools.
The problem with bitcoin is that now that the network has gotten huge, Mining centralization is taking place. This is true for both: hardware production and hashing power. It really damages the core principles of forming bitcoin, to begin with.
Industrial and small-scale miners alike often converge towards pools, which results in them receiving a steady payout at the cost of sacrificing autonomy – Core dev Matt Corrallo recently published a proposal for remedying this.
Miners can not afford to crash the whole bitcoin, because, they have a stake in bitcoin because they did very boldly go out and purchase purpose-built hardware, peripheral equipment/space, etc and spent tremendous amounts of electricity to earn transaction fees and block rewards. They wouldn’t want to shut themselves out.
Thus, the bitcoin, 51% attacks are not used. in that, they take aim at one of the cryptocurrency’s core value propositions – transaction finality. If successfully carried out, a 51% attack would undermine Bitcoin as a whole and possibly cause irreversible damage. A handful of prominent developers believe the PoW algorithm needs to be changed in order to mitigate the threat.
Thus, it is profitable, as of currently, to mine straight and steer away from such an attack. Who knows what the future holds.
