What is a Hard Fork?

    What is a Hard Fork

    Hard Fork Overview

    The use of cryptos has become quite normal in society today. Even those who promised themselves that they will never embrace anything related to crypto coins have changed their minds. Crypto coins such as BTC, ETH, etc., are now powered by blockchain. Changing the basic protocol of this blockchain is known as forking. Community members and developers can initiate a fork to change the blockchain protocol, i.e., an upgrade to the network. Changes can be major or minor. A hard fork occurs when a developer or community member changes the blockchain protocol radically. The purpose of this article is to gain a greater understanding of this type of fork.

    Overview of Forks on a Blockchain

    Before jumping right to the discussion of a Hard Fork, let us explain some stuff about the forks on a blockchain. If we want to put it simply, a blockchain is pretty much like a data block set. These data blocks have a link with each other by secure cryptographic keys making a chain of blocks that go back to the initial block.

    Hence, you might picture the blockchain as a straight pathway built out of blocks connected with each other. FYI, the blocks here are chained together via a consensus that is agreeable among all the blocks. So, if one wants to upgrade the system, they would have to change the consensus on all the blocks. Now, such a consensus can’t possibly happen as the blocks are connected via a functionally rigid set of rules. Therefore, developers and community members prefer to accomplish the task of making changes to a blockchain by using a fork. Doing so spares them the unnecessary hassle of rewriting every block individually.

    A fork is achieved on a blockchain when the original software gets duplicated, and the developer adds the changes they want to it. It is a well-known fact that two separate blockchains can’t exist together. Thus, the newly created blockchain bifurcates and creates a fork-like deviation from the primary blockchain.

    Understanding a Hard Fork

    In order to comprehend a little better about what a Hard Fork is, one must first grasp the concept of blockchain technology properly. A blockchain is, as its name suggests, a chain built with numerous blocks of data that serves as a digital registry. In this registry, every new block becomes valid only after network validators have authenticated the preceding one. One can trace the data on a blockchain even back to the initial transaction on the network. It is the reason behind our being capable of seeing the first-ever block on the BTC blockchain.

    So, coming to the Hard Fork, it is basically a lasting deviation from the latest edition of a blockchain. This, in turn, brings about the severance of a blockchain. It is because some nodes lose their ability to meet consensus, and two dissimilar versions of the network in concern run independently from each other.

    All this signifies that a fork is generated on a blockchain where one path keeps adhering to the existing set of rules, while the second path starts following a fresh set of rules. Such forks lack any backward compatibility. So, once the new version is generated, it becomes invalid in the eyes of the old one.

    Among such forks, hard ones are frequently regarded as being dangerous. Why? Because they often experience a chain split. If a split takes place between the miners responsible for securing the network and the nodes that assist in authenticating transactions, bad consequences will arise. As a result of this split, the network loses its security and faces an increased risk of attacks.

    You might know that a common method to do harm to a blockchain is to execute a 51% attack. This is an attack where a clique of miners is capable of possessing more than 51% of the total computing power responsible for securing a network. After that, they utilize it to modify the history of that blockchain. We have seen many times that networks created as a result of hard-forking changes have been attacked by over 51 percent, especially when bad actors have spent the same funds twice. This type of attack allows perpetrators to restructure blocks and double-spend using their superior computing power.

    Another great risk of radically changing a network protocol is replay attacks. These types of attacks happen when a malevolent entity seizes a transaction on a forked network and replicates that data on another chain. If a hard-forking change lacks any replay attack defence, both these transactions will be considered legit. That means one can shift another users’ funds with no control over them.

    Why would a Developer Opt for a Hard Fork anyway?

    Now, you may ask why this type of fork even occurs when there are huge security risks. Well, it’s not really hard to see. Performing radical changes to a blockchain is vital to improve the network as a whole. Why? Because blockchain technology is not static. In fact, it is seeing a constant evolution.

    This type of fork could sometimes even occur accidentally. Most of the time, such happenings get resolved fast, and once they realize what had occurred, those no longer meeting the consensus with the primary blockchain back off and start adhering to it. Likewise, hard-forking changes contributing to the addition of new features and network upgrades typically permit those falling out of consensus to join the primary chain again.

    The BTC blockchain has been subject to many such accidental radical changes in protocol till now. Such changes are not rare here, and one may not even notice them as they are dealt with and resolved extremely fast.

    Most such forks happen every time two miners come across the exact same block at a given moment. As the distribution of the consensus on the network begins, both miners see the block as legit at first and continue mining on dissimilar chains before they or a third miner adds the next block.

    That next block decides which will be the longest among chains. That means the other chain would be left behind to maintain the consensus. This leads miners to shift to the longest chain as the chain that has been left behind no longer remains money-making for mining BTC. Why? Because that way, they would find themselves mining a fork of the said network.

    When such forks occur, miners who come across the deserted block lose their Coinbase and transaction fee rewards. However, neither of the two transactions will be refuted, since both blocks were alike and contained similar transactions.

    Other such accidents that happened in the past played a role in code problems that were responsible for short-chain splits. Take the incident that happened back in the year 2013, for example. The incident saw the miners mining and broadcasting a block with an unforeseen number of total transaction inputs. As is supposed to occur, a number of nodes were unable to process it. This led to an accidental split. The problem was resolved only after several nodes downgraded their software in order to meet the consensus and dismiss this bigger block.

    Hard vs. Soft fork

    A Hard Fork and a Soft Fork are basically the same in a way. Why? Because whenever a crypto platform’s current code gets modified, a new version arises with an old version staying on the network.

    In the case of a soft fork, only a single blockchain will stay legit as users embrace the update. On the other hand, a hard one makes both the old and new blockchains coexist. This means that a user must update the software to function according to new rules. Both types of forks cause a split. But a soft fork generates one blockchain while a hard one results in two.

    Keeping in mind the security differences between these two forks, almost all developers and community members dismiss a soft fork and prefer a hard one instead. It is because of the privacy they offer.


    As you can see, a Hard Fork is a thorough modification of a blockchain protocol. Developers and community members from all over the globe have wholeheartedly embraced this particular type of forking over the soft one. And, this is not a sudden phenomenon. This type of fork has allowed the developers to update the network and add new, extra features. Blockchain technology is not known for being stagnant. It is an ever-changing entity. Thus, it is vital to keep updating the network often. While most of such forks are intentional, some occur as a result of an accident. Whatever the cause may be, the outcome is two blockchains coexisting and running independently of each other.

    Despite all its benefits, there are several coins as well. Security risks are one of those, making these forks dangerous and vulnerable to many attacks like 51% and replay attacks. But even after knowing this, most developers and users prefer this method for its privacy instead of the soft fork. The trend will likely continue into the future.