What is Hard Fork (Blockchain)?

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A fork is an update or upgrade to the blockchain’s software protocol which results in a split in the main blockchain network. Blockchain requires updates and upgrades to function effectively like traditional websites and apps. However, a blockchain network requires all users to agree before implementing an update, and the solution used is to create a new version of the blockchain and have all users vote to switch to that new and upgraded version.

What is a Hard Fork

A hard fork on a blockchain is when the protocol is updated or changed in such a way that the old blockchain and the resulting blockchain are incompatible.

When this happens, the old nodes will not accept the newly updated blocks, and the new blockchain will operate on new mechanisms that constantly reject blocks from the old blockchain. This is often referred to as a “backward-incompatible” software update.

A hard fork occurred on the Bitcoin blockchain over a disagreement in the Bitcoin community on the best approach for scaling the network. On one side of the argument were members who wanted to increase the block size. On the other side were those members who opposed such changes. Later on, those who wanted to increase the size of the block followed the Bitcoin Cash fork, while those who opposed such changes remained on the main Bitcoin network. Although Bitcoin and Bitcoin Cash now run on different blockchains, they still share the same history before the fork occurred.

Hard Fork vs. Soft Fork

A major difference between a hard fork and a soft fork is backward compatibility. In a hard fork, each chain splits into two and users need to pick what network to continue with. While in a soft fork, the network’s rules are updated but the split chains can coexist and older nodes can still verify transactions.

There have been a lot of arguments in the Blockchain and crypto space over which type of fork is best for upgrading blockchain networks. A soft fork is considered the milder option of the two but it has its risks. The most prominent of these risks is the fact that a soft fork can be used by bad actors to deceive full-node users and miners into validating blocks that violate the rules of the blockchain. If a group of people on the blockchain manage to create new rules without the knowledge of the full node users on the network, the security of the network can be endangered.

A hard fork, on the other hand, also has its challenges. First, hard forks usually lead to division in communities.  Second, many argue that hard forks are dangerous because they split the hashing power of the network, which reduces the network’s security and processing capacity overall.