Open source blockchain computing platform

Ethereum Classic is an open source, blockchain-based distributed computing platform featuring smart contract (scripting) functionality.[1] It supports 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.[2] The Ethereum project's mainnet initially released via Frontier on 30 July 2015. However, due to a hack of a third-party project, the Ethereum Foundation created a new version of the Ethereum mainnet on 20 July 2016 with an irregular state change implemented that erased The DAO theft from the Ethereum blockchain history.[2] The Ethereum Foundation applied their trademark to the new, altered version of the Ethereum blockchain; Ethereum (ticker: ETH).[2] The older, unaltered version of Ethereum was renamed and continued on as Ethereum Classic (ticker: ETC).[2]

Ethereum Classic's native Ether token is a cryptocurrency traded on digital currency exchanges under the ticker symbol ETC.[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 Ethereum Classic (ETC) monetary policy seeks the same goals as Bitcoin of being mechanical, algorithmic, and capped. ETC can be exchanged for network transaction fees or other assets, commodities, currencies, products, and services.

Ethereum Classic provides a decentralized Turing-complete virtual machine, the Ethereum Virtual Machine (EVM), which can execute scripts using an international network of public nodes. The virtual machine's instruction set is Turing-complete in contrast to others like Bitcoin Script. Gas, an internal transaction pricing mechanism, is used to mitigate spam and allocate resources on the network.[4]

Milestones[edit] Frontier[edit]

Several codenamed prototypes of the Ethereum platform were developed by the Ethereum Foundation, as part of their Proof-of-Concept series, prior to the official launch of the Frontier network. Ethereum classic would later follow this codebase after the DAO incident.

Date Block Milestone Name 2015-07-30 0 Frontier 2015-09-08 200,000 Ice Age 2016-03-15 1,150,000 Homestead 2016-07-20 1,920,000 The DAO Bailout 2016-10-24 2,500,000 Gas Reprice 2017-01-13 3,000,000 Die Hard 2017-12-11 5,000,000 Gotham 2017-12-11 5,000,001 5M20 Era 2 2018-05-29 5,900,000 Defuse Difficulty Bomb 2019-09-12 8,772,000 Atlantis 2020-01-11 9,573,000 Agharta 2020-03-17 10,000,001 5M20 Era 3 2020-06-01 10,500,839 Phoenix The DAO Bailout[edit]

In 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,[5] the Ethereum network split into two separate blockchains – the altered history was named Ethereum (ETH) and the unaltered history was named Ethereum Classic (ETC).[2]

The new chain with the altered history was branded as Ethereum (ticker: ETH) with the BIP-44 Coin Index 60 and EVM Chain ID 1 attributed to it by the trademark owning Ethereum Foundation. On this new chain, the history of the theft was erased from the Ethereum blockchain history.[6] Some members of the Ethereum community ignored the attempt to rewrite history and continued to participant on the original Ethereum network. The non-fork chain with an unaltered history continued on as Ethereum Classic (ticker: ETC) with the BIP-44 Coin Index 61 and EVM Chain ID 61.[2] Security Vulnerabilities Disclosed[edit]

On 28 May 2016, a paper was released detailing security vulnerabilities with The DAO that could allow ether to be stolen.[7] On 9 June 2016, Peter Vessenes publicly discloses the existence of a critical security vulnerability overlooked in many Solidity contracts, a recursive call bug. On 12 June 2016, Stephan Tual publicly claims that The DAO funds are safe despite the newly-discovered critical security flaw.

The Carbon Vote[edit]

On 15 July 2016, a short notice on-chain vote was held on TheDAO hard fork.[8] Of the 82,054,716 ETH in existence, only 4,542,416 voted for a total voter turn out of 5.5% of the total supply on 16 July 2016; 3,964,516 ETH (87%) voted in favor, 1/4 of which came from a single address, and 577,899 ETH (13%) opposed TheDAO fork.[8] The expedited process of the Carbon Vote drew criticism from opponents of the TheDAO fork. While proponents of the fork were quick to market the vote as an effective consensus mechanism and pushed forward with TheDAO fork four days later.[9]

Block 1,920,000[edit]

The first Ethereum Classic block that was not included in the forked Ethereum chain was block number 1,920,000, which was generated by Ethereum Classic miners on 20 July 2016.[8][10]

Defuse Difficulty Bomb[edit]

A mechanism called the Difficulty Bomb was designed to push the Ethereum chain from Proof-of-Work consensus mechanism to Proof-of-Stake in the future by exponentially increasing the difficulty of mining. This Difficulty Bomb was added to the network on block 200,000 in an upgrade named Ice Age. While Ethereum Classic participants debated the merit of the Difficulty Bomb, a network upgrade called Die Hard at block 3,000,000 delayed the effects of the mechanism. Once the network participants came to consensus on the issue, Ethereum Classic upgraded its network on block 5,900,000 to permanently defuse the Difficulty Bomb. This abandoned a future with Proof-of-Stake and committed the network to the Proof-of-Work consensus mechanism.

Characteristics[edit] Ether (ETC) ETC Logo Denominations Plural Ether(s) Symbol Ξ Ticker symbol ETC Nickname Ether Classic, Eth Classic, Classic Previous names Ethereum, ETH, Eth Precision 18 Subunits 10−9 Gwei 10−18 Wei Development Original author(s) Vitalik Buterin, Gavin Wood White paper ethereum whitepaper Implementation(s) EVM 61 Initial release Frontier / 30 July 2015; 4 years ago (2015-07-30) Latest release Phoenix / 1 June 2020; 1 day ago (2020-06-01) Code repository github.com/ethereumclassic Development status Active Written in C++, Go, Python, Rust, Scala Operating system Cross-platform Developer(s) Open-Source Software Development Source model Open-Source Model License Open-Source Licenses Website ethereumclassic.org Ledger Ledger start 30 July 2015; 4 years ago (2015-07-30) Split height #1,920,000 / 20 July 2016; 3 years ago (2016-07-20) Split from Ethereum (ETH) Split ratio 1:1 Timestamping scheme Proof-of-Work - Ethash Merged mining parent Ethereum (ETH) Hash function Keccack Issuance schedule Block reward reduction of 20% every 5,000,000 blocks. Block reward 3.2 ETC Block time 13 secs Block explorer BlockScout, Expedition Circulating supply 118,700,000 Supply limit 210,700,000 Valuation Exchange rate $12 (Feb. 2020) Market cap $1.4 billion (Feb. 2020)

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.[11][12] By design, the blockchain is inherently resistant to modification of the data. It is an open, distributed ledger that records transactions between two parties efficiently and in a verifiable and permanent way.[13] Unlike Bitcoin, Ethereum Classic operates using accounts and balances in a manner called state transitions. This does not rely upon unspent transaction outputs (UTXOs). The state denotes the current balances of all accounts and extra data. The state is not stored on the blockchain, it is stored in a separate Merkle Patricia tree. A cryptocurrency wallet stores the public and private "keys" or "addresses" which can be used to receive or spend ether. These can be generated through BIP 39 style mnemonics for a BIP 32 "HD Wallet". In the Ethereum tech stack, this is unnecessary as it does not operate in a UTXO scheme. With the private key, it is possible to write in the blockchain, effectively making an ether transaction.

To send ether to an account, you need the Keccak-256 hash of the public key of that account. Ether accounts are pseudonymous in that they are not linked to individual persons, but rather to one or more specific addresses.

Ether[edit]

Ether is a fundamental token for operation of Ethereum Classic, which thereby provides a public distributed ledger for transactions. It is used to pay for gas, a unit of computation used in transactions and other state transitions. Additionally, this currency is commonly referred to as Ethereum, Eth, Classic or ETC.

It is listed under the ticker symbol ETC and traded on cryptocurrency exchanges, and the Greek uppercase Xi character (Ξ) is generally used for its currency symbol. It is also used to pay for transaction fees and computational services on the Ethereum Classic network.[14]

Addresses[edit]

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). In hexadecimal, 2 digits represent a byte, meaning addresses contain 40 hexadecimal digits. An example of an Ethereum Classic address is 0xb794f5ea0ba39494ce839613fffba74279579268. Contract addresses are in the same format, however, they are determined by sender and creation transaction nonce.[15] User accounts are indistinguishable from contract accounts given only an address for each and no blockchain data. Any valid Keccak-256 hash put into the described format is valid, even if it does not correspond to an account with a private key or a contract. This is unlike Bitcoin, which uses base58check to ensure that addresses are properly typed.

Monetary Policy[edit]

On 11 December 2017, the total supply of Ether on Ethereum Classic was hard capped at 210,700,000 ETC 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. Socially, this block reward reduction event has taken the moniker of "The Fifthening."

Date 5M20 Era Block Block Reward Total Era Emission 2015-07-30 Era 1 1 5 ETC 25,000,000 ETC 2017-12-11 Era 2 5,000,001 4 ETC 20,000,000 ETC 2020-03-17 Era 3 10,000,001 3.2 ETC 16,000,000 ETC 2022-04-15 Era 4 15,000,001 2.56 ETC 12,800,000 ETC 2024-05-07 Era 5 20,000,001 2.048 ETC 10,240,000 ETC Code is Law[edit]

The people who continued with Ethereum Classic advocate for blockchain immutability, and the concept that "code is law" [16] against the pro-fork side (Ethereum) which largely argued for extra-protocol intentionality, decentralized decision-making, and conflict resolution.[17]

Attacks[edit] TheDAO Fork Replay Attacks[edit]

20 July 2016, due to reliance on the same clients, TheDAO fork creates a replay attack where a transaction is broadcast on both the ETC and ETH networks. 13 January 2017, the Ethereum Classic network is updated to resolve transaction replay attacks. The networks are now official operating separately.[8]

RHG Sells Stolen ETC[edit]

10 August 2016, the ETH proponent Robin Hood Group transfers 2.9 million stolen ETC to Poloniex in an attempt to sell ETC for ETH on the advice of Bitly SA; 14% is successfully converted to ETH and other currencies, 86% is frozen by Poloniex.[8] 30 August 2016, Poloniex returns the ETC funds to the RHG. They set up a refund contract on the ETC network.

Classic Ether Wallet (CEW) Website Attack[edit]

On 29 June 2017, the Ethereum Classic Twitter account made a public statement indicating reason to believe that the website for Classic Ether Wallet had been compromised. The Ethereum Classic Twitter account confirmed the details released via Threatpost. The Ethereum Classic team worked with Cloudflare to place a warning on the compromised domain warning users of the phishing attack.[18]

51% Double Spend Attack[edit]

In January 2019, Ethereum Classic was subject to double-spending attacks.[19][20]

References[edit] ^ Vigna, Paul (28 October 2015). "BitBeat: Microsoft to Offer Ethereum-Based Services on Azure". The Wall Street Journal (Blog). News Corp. Retrieved 17 February 2016. ^ a b c d e f Vigna, Paul (1 August 2016). "The Great Digital-Currency Debate: 'New' Ethereum Vs. Ethereum 'Classic'". The Wall Street Journal (Blog). News Corp. Retrieved 5 March 2020. ^ Russel, Jon (11 June 2018). "Coinbase will add Ethereum Classic to its exchange 'in the coming months'". TechCrunch.com. TechCrunch. Retrieved 5 March 2020. ^ Tapscott, Don (2016). Blockchain revolution : how the technology behind bitcoin is changing money, business, and the world. Toronto, Ontario, Canada: Portfolio/Penguin. ISBN 978-0670069972. ^ Waters, Richard (18 June 2016). "'Ether' brought to earth by theft of $50m in cryptocurrency". Financial Times. Retrieved 19 October 2018. ^ Leising, Matthew (13 June 2017). "Ether thief remains mystery year after $55 million heist". www.bloomberg.com. Bloomberg News. ^ Popper, Nathaniel (27 May 2016). "Paper Points Up Flaws in Venture Fund Based on Virtual Money". The New York Times. ISSN 0362-4331. Retrieved 12 July 2017. ^ a b c d e Andreas M. Antonopoulos, Gavin Wood (2018): "Ethereum timeline" . In Mastering Ethereum: Building Smart Contracts and DApps, page 329. O'Reilly Media; 424 pages. ISBN 9781491971918 ^ De Jesus, Cecille (19 July 2016). "The DAO Heist Undone: 97% of ETH Holders Vote for the Hard Fork". Futurism, LLC. Archived from the original on 7 August 2017. Retrieved 16 May 2017. ^ Matthew Leising (2017-06-13): "The Ether Thief". Online article, Bloomberg. Accessed on 2019-02-16. ^ "Blockchains: The great chain of being sure about things". The Economist. 31 October 2015. Retrieved 18 June 2016. The technology behind bitcoin lets people who do not know or trust each other build a dependable ledger. This has implications far beyond the crypto currency. ^ Narayanan, Arvind; Bonneau, Joseph; Felten, Edward; Miller, Andrew; Goldfeder, Steven (2016). Bitcoin and Cryptocurrency Technologies: a Comprehensive Introduction. Princeton: Princeton University Press. ISBN 978-0-691-17169-2. ^ Iansiti, Marco; Lakhani, Karim R. (January 2017). "The Truth About Blockchain". Harvard Business Review. Harvard University. Retrieved 17 January 2017. The technology at the heart of bitcoin and other virtual currencies, blockchain is an open, distributed ledger that can record transactions between two parties efficiently and in a verifiable and permanent way. ^ Popper, Nathaniel (27 March 2016). "Ethereum, a Virtual Currency, Enables Transactions That Rival Bitcoin's". New York Times. Archived from the original on 24 July 2016. Retrieved 2 September 2016. ^ Wood, Gavin (3 February 2018). "ETHEREUM: A SECURE DECENTRALISED GENERALISED TRANSACTION LEDGER (EIP-150)". yellowpaper.io. Archived from the original on 3 February 2018. Retrieved 3 February 2018. ^ Pearson, Jordan (27 July 2016). "The Ethereum Hard Fork Spawned a Shaky Rebellion". Motherboard. Retrieved 15 May 2017. ^ Primavera De Filippi (11 July 2016). "A $50M Hack Tests the Values of Communities Run by Code". Motherboard. Retrieved 15 May 2017. ^ Russon, Mary-Ann (30 June 2017). "Classic Ether Wallet has been hacked – do not use it to send currency". International Business Times. ^ Kharif, Olga (7 January 2019). "Ethereum Classic Movements Halted by Coinbase on Signs of Attack". Bloomberg. ^ Goodin, Dan (7 January 2019). "Almost $500,000 in Ethereum Classic coin stolen by forking its blockchain". Ars Technica. External links[edit]

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