Ethereum Classic (ETC): Comprehensive Overview
Core Definition and Technology
Ethereum Classic is a blockchain-based distributed computing platform that offers smart contract functionality and is open source, supporting a modified version of Nakamoto consensus via transaction-based state transitions executed on a public Ethereum Virtual Machine (EVM). Ethereum Classic maintains the original, unaltered history of the Ethereum network.
Blockchain Architecture
Ethereum Classic is a blockchain-based distributed computing platform that offers smart contract scripting functionality and supports a modified version of Nakamoto consensus via transaction-based state transitions executed on a public Ethereum Virtual Machine (EVM). The validity of each ether is provided by a blockchain, which is a continuously growing list of records called "blocks" that are linked and secured using cryptography, and by design, the blockchain is inherently resistant to modification of the data.
Project History and Founding
On 20 July 2016, as a result of the exploitation of a flaw in The DAO project's smart contract software, and subsequent theft of $50 million worth of Ether, the Ethereum network split into two separate blockchains – the altered history was named Ethereum (ETH) and the unaltered history was named Ethereum Classic (ETC).
There is no individual founder of Ethereum Classic. The platform originated as a hard fork of the Ethereum blockchain network, which was originally founded by Vitalik Buterin. ETC emerged as a result of a conflict within the Ethereum community, with some members believing in the immutable preservation of the blockchain, leading to the creation of Ethereum Classic.
The DAO Incident
Early in the history of the Ethereum blockchain, a decentralized autonomous organization (DAO) called "The DAO" raised millions of dollars to create an opportunity for crypto-based investments. The DAO was based on a set of smart contracts which ended up being hacked and resulted in many Ethereum users losing their valuable cryptocurrency. A flaw in The DAO's code led to a hack, resulting in the loss of about 3.6 million ether, worth approximately $50 million at the time.
Development Teams
December 11, 2016: IOHK's ETC development team forms, led by Ethereum founding member Charles Hoskinson. February 20, 2017: The ETCDEVTeam forms, led by early ETC developer Igor Artamonov (splix).
Primary Use Cases and Applications
Its main function is as a smart contract network, with the ability to host and support decentralized applications (DApps). Ethereum Classic supports smart contracts, code that automatically executes under specific conditions. This allows developers to easily build decentralized applications like DAOs and stablecoins.
International payments is an especially attractive use case for ETC because it is such a secure crossborder cryptocurrency, and it is programmable. Good use cases may be for payment of imports, collections of exports, and for salaries or contractor fees for international and remote employees or contractors. Because ETC has the same monetary policy as BTC (and it is programmable through smart contracts) then it is a perfect store of value for corporate treasuries.
Consensus Mechanism and Network Security
The consensus mechanism that ETC and BTC use is popularly called "proof of work" for simplicity but the real name of the system is "Nakamoto Consensus". In this system, miners solve complex mathematical problems to validate transactions and secure the network. The first miner to solve the problem gets the opportunity to add a new block to the blockchain and is rewarded with ETC for their efforts.
While Ethereum moved to a Proof of Stake (PoS) model in September 2022, Ethereum Classic chose to remain Proof of Work (PoW) as the consensus mechanism to validate transactions in an effort to ensure maximum decentralization and censorship resistance.
Mining Algorithm Evolution
In response, the Ethereum Classic development community considered several network upgrades and ultimately adopted a modified version of the Ethash proof-of-work (PoW) consensus algorithm, known as ETChash. This change was implemented through the "ECIP-1099 Thanos Upgrade" in November 2020. The upgrade recalibrated the Directed Acyclic Graph (DAG) by reducing its size and slowing its growth rate by half, enabling 3GB Ethash mining hardware to continue securing the network.
Network Security Status
Following Ethereum's transition to a proof-of-stake consensus mechanism in 2022, Ethereum Classic achieved a notable milestone by becoming the largest and most secure proof-of-work blockchain supporting smart contract functionality. In 2025, the network's ETChash hashrate surpassed 300 terahashes per second (TH/s), a level not observed since Ethereum's DeFi summer boom cycle.
Historical Security Challenges
Ethereum Classic (ETC) has experienced two major 51% double-spending attacks in its history. These attacks exploit the decentralized nature of the network by gaining control of more than 50% of its mining power, allowing malicious actors to reorganize the blockchain, manipulate transactions, and double-spend digital assets. The first significant incident occurred in January 2019, when Ethereum Classic was targeted by a double-spending attack resulting in approximately US$1.1 million worth of ETC being fraudulently spent.
Tokenomics
Supply Structure
ETC is digital gold because it is a proof of work blockchain, thus the cost to produce the money is the same as the cost to produce the blocks, and it has a fixed monetary policy with a supply cap of 210,700,000. The maximum supply is thus 210,700,000 ETC, roughly ten times that of Bitcoin (BTC), while ETH has no cap.
Distribution and Initial Allocation
The original distribution event occurred through a public token sale managed by the Ethereum Foundation, which sold roughly 60 million ETH (80% of the initial 72 million ETH supply). The remaining 12 million ETH (20% of the initial supply) were allocated to the Foundation and early contributors. When Ethereum and Ethereum Classic split following the DAO fork (on July 20, 2016), holders of ETH received equivalent amounts of ETH and ETC.
Inflation/Deflation Mechanics
On 11 December 2017, the total supply of Ether on Ethereum Classic was hard capped at ETC 210,700,000 via the Gotham hard fork upgrade. This added a bitcoin-inspired deflationary emission schedule that is documented in Ethereum Classic Improvement Proposal (ECIP) 1017. The emission schedule, also known as "5M20", reduces the block reward by 20% every 5,000,000 blocks.
Current Supply Metrics
Based on available data, the circulating supply of ethereum-classic (ETC) has been in the ballpark of the mid-100-million range (roughly around 147 million ETC) in recent years, trending upward slowly as block rewards continue until the cap is approached.
Unique Value Proposition and Philosophy
Existing in response to contract censorship on sister chain Ethereum™ (ETH) and to uphold and preserve the principle of Code is Law, Ethereum Classic (ETC) has proven its ability to resist censorship against all odds, and deliver the original Ethereum vision of unstoppable applications.
It upholds the concept of 'Code is Law', meaning that the rules and regulations of a decentralized network are enforced solely through its underlying code. The Ethereum Classic community stresses the core principals of censorship resistance and (most prominently) immutability. The Ethereum Classic community governs the network by the motto "Code is Law," which instills the belief that ETC transactions and dApps are truly censorship-resistant and immune to any third party interference.
Decentralization Philosophy
Ethereum Classic doesn't have any ICO or VC funding, big development team, or well funded foundation or corporation managing it. All these parts in the ecosystem are growing organically and in a distributed manner globally not only because the world is realizing that ETC has these true principles, but because its decentralist principles are actually encoded in its system.
Competitive Advantages
Ethereum Classic's unique attributes are a combination of the following features: Proof-of-Work: ETC is a will remain as a proof-of-work blockchain which is the most secure consensus mechanism known to man. Sound money: ETC is digital gold because it is a proof of work blockchain, thus the cost to produce the money is the same as the cost to produce the blocks, and it has a fixed monetary policy with a supply cap of 210,700,000. Programmability: ETC is programmable with smart contracts making it much more versatile and useful than other simpler cryptocurrency chains such as Bitcoin or Litecoin. Full replication: ETC is most secure because it is fully replicated across all nodes of the network. Where other smart contract blockchains are implementing "sharding", "parachains", or "sidechains" that reduce security, ETC will remain fully replicated.
Development Activity and Roadmap
This phase covers recent and ongoing developments and initiatives that aim to improve and grow Ethereum Classic. It includes the implementation of the Atlantis, Agharta, and Phoenix hard forks that made Ethereum Classic fully compatible with Ethereum, the launch of the MESS protocol that protects the network from 51% attacks, the introduction of the Thanos upgrade that extends the mining life of the platform, and the integration with other blockchain platforms and technologies such as Cardano, IPFS, and Filecoin.
ETC's structure varies from most blockchain projects, incorporating multiple development teams (IOHK, ETC Labs, and ETC Cooperative), each with their own goals. In general, most of these teams have focused on providing sidechain scaling solutions, improving development tools (SDKs), and promoting cross-chain transactions so others can build on Ethereum Classic. Some of these efforts, including Connext's state channels and ChainSafe's bridge to Ethereum and Cosmos SDK-based chains, have already launched.
Market Position
Following Ethereum's transition to a proof-of-stake consensus mechanism in 2022, Ethereum Classic achieved a notable milestone by becoming the largest and most secure proof-of-work blockchain supporting smart contract functionality. In 2025, the network's ETChash hashrate surpassed 300 terahashes per second (TH/s), a level not observed since Ethereum's DeFi summer boom cycle. Ethereum Classic subsequently established itself as the leading blockchain utilizing the Ethash algorithm family.
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