A successful blockchain must be capable of executing upgrades to its protocol in a secure and well ordered fashion. Actuating substantial improvements has proven to be a brutally difficult challenge for many blockchains - in terms of planning, development, implementation, and overall user experience. In the blockchain world, a ‘fork’ can be thought of as a technological split, an update to the code underlying a decentralized ledger resulting in a major modification. Forks have typically fallen into two distinct categories: hardforks and softforks. A hardfork represents an event where the new chain is not meant to be compatible with the old one; a famous example of this is Bitcoin Cash’s split from Bitcoin. Softforks, on the other hand, encapsulate substantial software changes while retaining reconcilability with the original chain. Hardforks can occur for many reasons, including innovation, repairing damage from a hack, and failure to reach consensus on a softfork.
Regardless of what necessitates the fork itself, it’s important that the transition from one phase to the next happen securely for everyone involved, from network node operators to everyday users. According to Niahm Ahern and Olga Hyrniuk of Input Output Global, “Traditionally, when conducting a hardfork, the protocol would stop operating, new rules and changes would be implemented, and the chain would restart.” This method of executing a significant revision to a blockchain with a large user base and a valuable ecosystem in one massive update “can cause a range of complexities.” Cardano’s novel approach to implementing protocol improvements is defined by the Hardfork Combinator, which flips the concept of a fork on its head by combining (rather than diverging) the old chain with the new chain. The fact that the combinator can achieve this without sacrificing continuity of user experience or causing network interruption of any kind is a far-reaching accomplishment that sets Cardano apart from its contemporaries.
How does it work?
The Hardfork Combinator explores uncharted territory by establishing a ‘generic’ system for connecting protocols in an agnostic manner that maintains underlying chain continuity. Cardano’s development roadmap has been split into eras (Byron, Shelley, Goguen, Basho, Voltaire) that must be able to establish new ledger rules without causing conflict on the consensus layer. This approach is not feasible or efficient on other blockchains, but becomes a reality on Cardano thanks to the Combinator’s ability to define a new type of block for the consensus layer to process, a block which is an amalgam of other block types. Individual ledgers can thus behave as if they’re ‘the only game in town’ and the consensus layer doesn’t need to know anything about the individual ledgers. The Combinator functions as malleable yet resilient glue connecting an evolving tapestry of ledgers and preserves the history of the Cardano blockchain from its genesis into the far future. This level of immutability was not possible before because other systems are required to restart completely and leave the old ledger behind in order to make meaningful changes; history is inherently rewritten in the process.
By gradually and consistently adding new block types to the ‘definition’ of a block as communicated to the consensus layer, Cardano can shift from one era of development in a deliberate and nuanced fashion that occurs in incremental installments and gives developers, node operators, exchanges, and end users ample time to make the measured adjustments necessary to stay up-to-date.
The Hardfork Combinator: Cardano’s Key to Longevity
Blockchains that cannot evolve efficiently are doomed to become stagnant and brittle. Ethereum’s haphazard and reactionary approach to changes on the protocol level has exposed the project and its stakeholders to unnecessary risks and obstacles. The Hardfork Combinator concept was originally chosen because it makes testing protocol switches in advance of implementation much easier and more precise. This is a deceptively small detail that can seem a bit redundant if we’re assuming that the changes are well conceptualized and developed, then executed by skilled professionals. But experience has taught us to expect the unexpected when the rubber meets the road. Of course, there’s no way to know what to expect in the blockchain industry, so it’s best to plan as thoroughly as possible. Good planning demands a way of testing ideas before they’re implemented. A well tested piece of code is considered high-assurance, and this starts to become more of a prerequisite when highly consequential results are at stake.
The Hardfork Combinator is a groundbreaking tool designed to give Cardano unprecedented levels of assurance in its underlying code without sacrificing expressiveness or adaptability. Part of its magic is that if it does its job properly, the Combinator will make the average user’s interactions with Cardano a smooth, secure, and drama free experience. Users can expect to enjoy a number of upgrades to the Cardano network coming very soon with the Vasil hardfork!