Published on: 2017-11-09T18:18:17+00:00
In a recent discussion on the bitcoin-dev mailing list, the threat of a majority attack, also known as a "51% attack," on Bitcoin was raised. This attack involves a majority of miners forming a cartel and invalidating blocks made by miners outside of their group. One proposed method for achieving this is through a soft fork that requires a signature from a set of keys known only to the cartel. While there is no technical mechanism in place to prevent such an attack, it is argued that miners are not incentivized to perform it as it would destroy confidence in Bitcoin and ultimately impact their revenues.However, it is noted that in practice, there exists an incentive to disrupt the market for transaction confirmation, as statism is profitable and a primary source of revenue is seigniorage. This presents a hefty incentive for those who feel threatened by Bitcoin's disruption of that privilege. The security model of Bitcoin is based on miners and merchants defending their mutually beneficial market from the state, rather than balancing power between them. Despite broad decentralization mitigating the risk to each individual, people must be willing to defend their mines and economic nodes, which requires personal risk.The discussion also touched on the importance of fullnodes in determining which set of rules to follow. If fullnodes do not care about the cartel's actions, then the group of miners that is larger wins. However, if fullnodes check one or the other set of rules, then that set of rules will win. Given current politics, it is likely that fullnodes will institute an anti-cartel rule in this case and reject the cartel, resulting in low hashrate for the cartel. Eventually, the cartel will be betrayed by one of its members mining the anti-cartel chain in return for fees and valuable block rewards.In conclusion, while it may not be feasible for one actor to gain a majority of hash power alone, collusion among a group of miners makes it possible. To ensure the continued security and integrity of the Bitcoin network, countermeasures must be put in place to prevent centralization of mining by force. Fullnodes need to be aware of the rules and reject any attempt to form a cartel. The ongoing discussion amongst those involved in Bitcoin development aims to address these concerns and find solutions that maintain the permissionless nature of mining.
Updated on: 2023-08-01T22:07:43.306394+00:00