Hard Fork

Hard Fork refers to a significant and incompatible change to a Blockchain protocol that results in a split in the Blockchain. This change is not backward-compatible, meaning that nodes running the old version of the software cannot validate blocks created by the new version. A hard fork creates two separate chains: one that follows the old rules and one that adheres to the new rules.

Examples:

• Bitcoin and Bitcoin Cash: In August 2017, Bitcoin underwent a hard fork, resulting in the creation of Bitcoin Cash (BCH). This fork was primarily driven by disagreements over block size and transaction speed.
• Ethereum and Ethereum Classic: In July 2016, Ethereum experienced a hard fork following the DAO hack, leading to the creation of Ethereum Classic (ETC) for those who wanted to maintain the original chain without reversing the hack.

Cases:

• In cases of governance disagreements within a Blockchain community, a hard fork can serve as a method for one faction to implement their proposed changes while allowing the other faction to continue on the original chain.
• Hard forks may also occur as a response to security vulnerabilities or bugs, allowing developers to address critical issues while leaving the original chain intact.