What is a Byzantium Fork?

Byzantium Fork is a term used in the blockchain and cryptocurrency space to refer to a specific type of software upgrade. It is part of the Ethereum Improvement Protocol (EIP) and is named after the ancient city of Byzantium.

The Byzantium Fork is a hard fork of the Ethereum blockchain, designed to improve the functionality and scalability of the network. It was implemented in October 2017 and was the first major upgrade to the Ethereum blockchain. The upgrade included several changes, including the introduction of the Ethereum Virtual Machine (EVM) and a new Proof-of-Stake consensus algorithm known as Casper.

The Byzantium Fork also introduced the ability to create and deploy new smart contracts, as well as support for zero-knowledge proofs, which allow users to create anonymous transactions. This allows for increased privacy on the Ethereum network, as well as increased scalability as more transactions can be processed in a shorter amount of time.

The Byzantium Fork also enabled the implementation of a new data structure called the Merkle Tree, which allows for faster and more efficient data storage on the blockchain. This feature is crucial for scalability, as larger datasets can be stored on the blockchain without having to be replicated on every node.

In addition to these features, the Byzantium Fork also introduced several other changes, such as support for atomic swaps, which allows users to exchange tokens without the need for a third-party intermediary, and a new rewards system for validators, which incentivizes the secure operation of the network.

Overall, the Byzantium Fork is a major upgrade to the Ethereum blockchain that has enabled a range of new features and improved the scalability and functionality of the network. It is a key part of the Ethereum Improvement Protocol, and is essential for the continued development of the Ethereum network.

Simplified Example

The Byzantine Fork is like a game of tug-of-war. Two teams, each with their own set of rules, are pulling a rope in opposite directions. The rules of both teams are so different that neither team can come to a consensus on which direction the rope should be pulled. This results in the rope being pulled back and forth without either team ever making any real progress. It's like the rope is stuck in a loop, going nowhere. This is what the Byzantine Fork is: a situation when two teams can't agree on which direction to take, resulting in a stalemate.

History of the Term Byzantium Fork

The term "Byzantium Fork" emerged in the context of Ethereum's development in the mid-2010s, as the Ethereum community envisioned a series of hard forks to upgrade the Ethereum network and address scalability and security concerns. The Byzantium Fork, also known as Istanbul Hard Fork, was the second major hard fork in Ethereum's history, following the Homestead Fork in 2016.

The Byzantium Fork was successfully implemented on October 18, 2017, marking a significant milestone in Ethereum's development. It introduced important improvements to the Ethereum network, laying the foundation for further upgrades and enhancing the network's scalability, security, and privacy features.


Example 1: The upgrade aimed to improve Ethereum's decentralization, scalability and security attributes.

Example 2: A hard fork of a cryptocurrency blockchain splits the blockchain in two, creating an old and new version. The new and old versions are incompatible, and all new transactions are recorded on the new chain.

Example 3: The hard fork included the EIP140, EIP658 EIP196, EIP197, EIP198, EIP211, EIP214, EIP100, EIP649.

Example 4: After the Byzantium Fork, the Ethereum developers continued to build the framework for the eventual switch to the proof-of-stake consensus mechanism. This consensus switch was implemented on September 15 2022.

  • Hard Fork: A hard fork is a change to the protocol of a blockchain that is not backward-compatible, meaning that all participants in the network must upgrade to the latest version of the software or risk becoming irrelevant on the network.

  • OHM Fork: The OHM fork is a term used in the cryptocurrency industry to refer to a type of software upgrade or change to the underlying code of a cryptocurrency.