Ethereum Classic is a blockchain-based distributed computing platform that offers smart contract (scripting) functionality.

[1] It is open source and supports a modified version of Nakamoto consensus via transaction-based state transitions executed on a public Ethereum Virtual Machine (EVM).

[3] Ether is created as a reward to network nodes for a process known as "mining", which validates computations performed on Ethereum Classic's EVM.

Implemented on 11 December 2017, the current ETC monetary policy seeks the same goals as bitcoin: being mechanical, algorithmic, and capped.

Gas, an internal transaction pricing mechanism, is used to mitigate spam and allocate resources on the network.

[7] On 9 June 2016, Peter Vessenes publicly disclosed the existence of a critical security vulnerability overlooked in many Solidity contracts, a recursive call bug.

On 12 June 2016, Stephan Tual publicly claimed that the DAO funds were safe despite the newly-discovered critical security flaw.

While Ethereum Classic participants debated the merits of the Difficulty Bomb, a network upgrade called "Die Hard" at block 3,000,000 delayed the effects of the mechanism.

Atlantis, activated in September 2019, enabled the Agharta upgrade, which included the outstanding Byzantium changes.

As with other cryptocurrencies, the validity of each ether is provided by a blockchain, which is a continuously growing list of records, called "blocks", which are linked and secured using cryptography.

[14] Unlike bitcoin, Ethereum Classic operates using accounts and balances in a manner called state transitions.

A cryptocurrency wallet stores the public and private "keys" or "addresses" which can be used to receive or spend Ether.

ETC is a fundamental token for operation of Ethereum Classic, which thereby provides a public distributed ledger for transactions.

[15] Ethereum Classic addresses are composed of the prefix "0x", a common identifier for hexadecimal, concatenated with the rightmost 20 bytes of the Keccak-256 hash (big endian) of the ECDSA public key (the curve used is the so-called secp256k1, the same as bitcoin).

This added a bitcoin-inspired deflationary emission schedule that is documented in Ethereum Classic Improvement Proposal (ECIP) 1017.

[21] On 20 July 2016, due to reliance on the same clients, the DAO fork created a replay attack where a transaction was broadcast on both the ETC and ETH networks.

[24][25] In response, the Ethereum Classic team initiated several network upgrades, including the adoption of a modified version of the Proof of Work (PoW) consensus algorithm called "ECIP-1049 Keccak256.