What is Selfish Mining?
Selfish mining is a strategy used by some cryptocurrency miners to increase their own profits at the expense of the overall network. In a traditional mining setup, miners compete to solve complex mathematical problems and validate transactions on the blockchain in order to receive rewards. However, selfish miners use a different approach: instead of contributing to the network, they withhold valid blocks from being broadcasted to other nodes, and work on finding another block privately.
The idea behind selfish mining is that by withholding blocks, the selfish miner can gain an advantage over the rest of the network. When the selfish miner finally does broadcast a block, it has a head start in solving the next block, giving it a higher chance of finding the next block before other miners. This results in the selfish miner earning more rewards and having a larger share of the network's overall mining power.
The problem with selfish mining is that it can lead to a concentration of mining power in the hands of a few individuals, which can have negative consequences for the overall security and stability of the network. A small group of selfish miners could potentially control a majority of the network's mining power, allowing them to manipulate the network for their own benefit. This could include censorship of transactions, double spending, or even a 51% attack, where a group of miners have the power to reverse transactions and disrupt the network.
To mitigate the risks associated with selfish mining, many cryptocurrencies have implemented measures to make it more difficult for miners to carry out the strategy. This includes using algorithms that are more resistant to centralization, and increasing the transparency of the network so that selfish mining behavior can be more easily detected.
Simplified Example
Selfish mining in cryptocurrency is like when one player in a game of catch keeps the ball to themselves and doesn't share it with the other players. In a game of catch, everyone is supposed to take turns throwing the ball and catching it. But if one player decides to keep the ball to themselves and not throw it to the others, it's not fair and ruins the game for everyone.
In the same way, in a cryptocurrency network, all the computers are supposed to work together to process transactions and create new blocks. But if one computer, or group of computers, decides to only work on their own blocks and not share them with the rest of the network, it's not fair and can slow down the whole system.
This is called selfish mining, and it's like the computer is being selfish and not playing by the rules. By doing this, the selfish miner can potentially make more money, but it also undermines the security and stability of the whole system.
Who Invented Selfish Mining?
The term "selfish mining" was introduced by Emin Gün Sirer and Ittay Eyal in their 2013 research paper titled "Selfish Mining: A Distributed Denial-of-Service Attack on Bitcoin-like Cryptocurrency Systems." In their study, Sirer and Eyal investigated a potential attack scenario where a miner, wielding significant hashing power, could manipulate the blockchain by withholding information about mined blocks. This tactic, termed "selfish mining," enabled the attacker to unfairly benefit in the mining process, undermining the overall efficiency and security of the network. Since its inception, the term "selfish mining" has been widely adopted in the cryptocurrency community to characterize this specific attack strategy. Subsequent research papers and discussions have delved deeper into the concept, contributing to a better understanding of potential vulnerabilities and security considerations in blockchain-based systems.
Examples
Selfish Mining Attack on Bitcoin: Selfish mining is a strategy used by some malicious miners in a cryptocurrency network to manipulate the network and increase their own profits at the expense of other miners. In a selfish mining attack on Bitcoin, a miner who controls a significant amount of hash power will mine blocks privately and not broadcast them to the network. When the miner sees that the network has discovered a new block, they will release their privately mined blocks, making it more likely that their blocks will be added to the blockchain instead of the blocks of other miners. This allows the selfish miner to earn more rewards and increase their share of the network's total hash power.
Double Spending Attack: Selfish mining can also be used as a double-spending attack in which a miner who controls a significant amount of hash power can use their control over the network to perform double-spending attacks. In this scenario, the miner can secretly mine two different blocks that contain conflicting transactions, and broadcast only the one that they want to confirm. By doing this, they can manipulate the network and cause the other miners to accept a block that they want to confirm, while rejecting a block that they do not want to confirm.
Mining Centralization: Selfish mining can also lead to mining centralization, which can have negative effects on the security and stability of a cryptocurrency network. If a single miner or a small group of miners control a significant portion of the network's hash power, they can use their control to manipulate the network, censor transactions, and potentially engage in malicious activities. This can lead to a loss of trust in the network, and can make it more susceptible to attacks and malicious actors.