A hard fork in Bitcoin

 

• Change in Rules: A hard fork involves altering the underlying rules or protocol of the Bitcoin network. This could involve changes like increasing the block size limit, modifying the mining algorithm, or implementing new features that are not backward compatible.
• Backward Incompatibility: Once a hard fork occurs, blocks and transactions that follow the new rules are no longer valid on the old blockchain, and vice versa. Nodes that have not upgraded to the new software will see these new blocks as invalid, causing a split in the blockchain.
• Creation of a New Blockchain: If the community does not unanimously agree to the change, this can lead to the creation of two separate blockchains. For example, one continues as Bitcoin (BTC), and the new one might be called something else, like Bitcoin Cash (BCH) after its hard fork in 2017.
• Community and Miner Support: For a hard fork to be successful, it needs significant support from miners, developers, and users. If enough nodes upgrade to the new software, the blockchain will continue with the new rules. If not, the blockchain might not gain traction, or it could lead to a contentious split where two cryptocurrencies exist.
• Replay Protection: Sometimes, to ensure that transactions on one chain do not get replayed on the other, developers implement “replay protection.” This prevents someone from spending coins on one chain and inadvertently spending them on the other chain as well.
• Examples: Notable hard forks in the Bitcoin ecosystem include Bitcoin Cash (from Bitcoin), which aimed at increasing block size to allow more transactions, and Bitcoin SV (from Bitcoin Cash), which sought to further increase scalability.