The Ethereum Project's logo, first used in 2014
|Original author(s)||Vitalik Buterin, Gavin Wood, Joseph Lubin|
|Initial release||30 July 2015|
|Written in||C++, Go, Rust|
|License||GPLv3, LGPLv3, MIT|
Ethereum is an open source, public, blockchain-based distributed computing platform and operating system featuring smart contract (scripting) functionality. It supports a modified version of Nakamoto consensus via transaction-based state transitions. Ether is a cryptocurrency generated by the Ethereum platform and used to compensate mining nodes for computations performed. Each Ethereum account has an ether balance and ether may be transferred from one account to another.
Ethereum provides a decentralized virtual machine, the Ethereum Virtual Machine (EVM), which can execute scripts using an international network of public nodes. The virtual machine's instruction set, in contrast to others like Bitcoin Script, is thought to be Turing-complete. "Gas", an internal transaction pricing mechanism, is used to mitigate spam and allocate resources on the network.
Ethereum was proposed in late 2013 by Vitalik Buterin, a cryptocurrency researcher and programmer. Development was funded by an online crowdsale that took place between July and August 2014. The system then went live on 30 July 2015, with 72 million coins "premined". This accounts for about 68 percent of the total circulating supply in 2019.
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, Ethereum was split into two separate blockchains – the new separate version became Ethereum (ETH) with the theft reversed, and the original continued as Ethereum Classic (ETC).
- 1 Etymology
- 2 History
- 3 Characteristics
- 4 Platform
- 5 Development governance and EIP
- 6 Criticisms
- 7 References
- 8 External links
Vitalik Buterin picked the name Ethereum after browsing Wikipedia articles about elements and science fiction, when he found the name, noting, "I immediately realized that I liked it better than all of the other alternatives that I had seen; I suppose it was the fact that sounded nice and it had the word 'ether', referring to the hypothetical invisible medium that permeates the universe and allows light to travel."
Ethereum was initially described in a white paper by Vitalik Buterin, a programmer involved with Bitcoin Magazine, in late 2013 with a goal of building decentralized applications. Buterin had argued that Bitcoin needed a scripting language for application development. Failing to gain agreement, he proposed development of a new platform with a more general scripting language.:88
Ethereum was announced at the North American Bitcoin Conference in Miami, in January, 2014. During the same time as the conference, a group of people rented a house in Miami: Gavin Wood, Charles Hoskinson, and Anthony Di Iorio, a Torontonian who financed the project. Di Iorio invited friend Joseph Lubin, who invited reporter Morgen Peck, to bear witness. Six months later the founders met again in a house in Zug, Switzerland, where Buterin told the founders that the project would proceed as a non-profit. Hoskinson left the project at that time.
Ethereum was officially with an unusually long list of founders. Anthony Di Iorio wrote "Ethereum was founded by Vitalik Buterin, Myself, Charles Hoskinson, Mihai Alisie, & Amir Chetrit (the initial 5) in December 2013. Joseph Lubin, Gavin Wood, & Jeffrey Wilke were added in early 2014 as founders." Formal development of the Ethereum software project began in early 2014 through a Swiss company, Ethereum Switzerland GmbH (EthSuisse). The basic idea of putting executable smart contracts in the blockchain needed to be specified before the software could be implemented; this work was done by Gavin Wood, then chief technology officer, in the Ethereum Yellow Paper that specified the Ethereum Virtual Machine. Subsequently, a Swiss non-profit foundation, the Ethereum Foundation (Stiftung Ethereum), was created as well. Development was funded by an online public crowdsale during July–August 2014, with the participants buying the Ethereum value token (ether) with another digital currency, bitcoin.
While there was early praise for the technical innovations of Ethereum, questions were also raised about its security and scalability.
Enterprise Ethereum Alliance (EEA)
In March 2017, various blockchain start-ups, research groups, and Fortune 500 companies announced the creation of the Enterprise Ethereum Alliance (EEA) with 30 founding members. By May, the nonprofit organization had 116 enterprise members—including ConsenSys, CME Group, Cornell University's research group, Toyota Research Institute, Samsung SDS, Microsoft, Intel, J. P. Morgan, Cooley LLP, Merck KGaA, DTCC, Deloitte, Accenture, Banco Santander, BNY Mellon, ING, and National Bank of Canada. By July 2017, there were over 150 members in the alliance, including recent additions MasterCard, Cisco Systems, Sberbank and Scotiabank.
|Code name||Release date||Release block|
Several codenamed prototypes of the Ethereum platform were developed by the Foundation, as part of their Proof-of-Concept series, prior to the official launch of the Frontier network. "Olympic" was the last of these prototypes, and public beta pre-release.
The Olympic network provided users with a bug bounty of 25,000 ether for stress testing the limits of the Ethereum blockchain. "Frontier" marked the tentative experimental release of the Ethereum platform in July 2015.
Since the initial launch, Ethereum has undergone several planned protocol upgrades, which are important changes affecting the underlying functionality and/or incentive structures of the platform.[non-primary source needed]
Protocol upgrades are accomplished by means of a soft fork of the open source code base.
The "Metropolis Part 1: Byzantium" soft fork took effect on 16 October 2017, and included changes to reduce the complexity of the EVM and provide more flexibility for smart contract developers. Byzantium also added supports for zk-SNARKs (from Zcash), with the first zk-SNARK transaction occurring on testnet on September 19, 2017.
The "Metropolis Part 2: Constantinople" hard fork, and the simultaneous "St. Petersburg" network upgrade, occurred at block number 7,280,000 on February 28, 2019.
The DAO event
In 2016 a decentralized autonomous organization called The DAO, a set of smart contracts developed on the platform, raised a record US$150 million in a crowdsale to fund the project. The DAO was exploited in June when US$50 million in ether were taken by an unknown hacker. The event sparked a debate in the crypto-community about whether Ethereum should perform a contentious "hard fork" to reappropriate the affected funds. As a result of the dispute, the network split in two. Ethereum (the subject of this article) continued on the forked blockchain, while Ethereum Classic continued on the original blockchain. The hard fork created a rivalry between the two networks.
After the hard fork related to The DAO, Ethereum subsequently forked twice in the fourth quarter of 2016 to deal with other attacks. By the end of November 2016, Ethereum had increased its DDoS protection, de-bloated the blockchain, and thwarted further spam attacks by hackers.[unbalanced opinion?]
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. 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. Unlike Bitcoin, Ethereum operates using accounts and balances in a manner called state transitions. This does not rely upon unspent transaction outputs (UTXOs). State denotes the current balances of all accounts and extra data. 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 Ethereum, 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.
|10−18||Wei, after cryptocurrency pioneer Wei Dai|
|Timestamping scheme||Proof-of-work Ethash|
|Issuance schedule||Block and Uncle/Ommer reward|
|Block reward||2 ETH (non-deterministic)|
|Block time||14-15 seconds on average|
Ether is a fundamental token for operation of Ethereum, 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. Mistakenly, this currency is also referred to as Ethereum.
It is listed under the ticker symbol ETH 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 network.
Ethereum 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 represents a byte, meaning addresses contain 40 hexadecimal digits. An example of an Ethereum address is 0xb794F5eA0ba39494cE839613fffBA74279579268. Contract addresses are in the same format, however they are determined by sender and creation transaction nonce. 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.
Comparison to bitcoin
- Its block time is 14 to 15 seconds, compared with 10 minutes for bitcoin.
- Mining of ether generates new coins at a usually consistent rate, occasionally changing during hard forks, while for bitcoin the rate halves every 4 years.
- For proof-of-work, it uses the Ethash algorithm which reduces the advantage of specialized ASICs in mining.
- Transaction fees differ by computational complexity, bandwidth use and storage needs (in a system known as gas), while bitcoin transactions compete by means of transaction size, in bytes.
- Ethereum uses an account system where values in Wei are debited from accounts and credited to another, as opposed to Bitcoin's UTXO system, which is more analogous to spending cash and receiving change in return.
The total supply of ether was around Ξ106.7 million as of July 5, 2019. In 2017, mining generated 9.2 million new ether, corresponding to a 10% increase in its total supply. Casper FFG and CBC are expected to reduce the inflation rate to between 0.5% to 2%. There is no currently implemented hard cap on the total supply of ETH.
Markets and stores
One issue related to using smart contracts on a public blockchain is that bugs, including security holes, are visible to all but cannot be fixed quickly. One example of this is the 17 June 2016 attack on The DAO, which could not be quickly stopped or reversed.
There is ongoing research on how to use formal verification to express and prove non-trivial properties. A Microsoft Research report noted that writing solid smart contracts can be extremely difficult in practice, using The DAO hack to illustrate this problem. The report discussed tools that Microsoft had developed for verifying contracts, and noted that a large-scale analysis of published contracts is likely to uncover widespread vulnerabilities. The report also stated that it is possible to verify the equivalence of a Solidity program and the EVM code.
Many uses have been proposed for Ethereum platform, including ones that are impossible or unfeasible. Use case proposals have included finance, the internet-of-things, farm-to-table produce, electricity sourcing and pricing, and sports betting. Ethereum is (as of 2017) the leading blockchain platform for initial coin offering projects, with over 50% market share.
Ethereum-based customized software and networks, independent from the public Ethereum chain, are being tested by enterprise software companies. Interested parties include Microsoft, IBM, JPMorgan Chase, Deloitte, R3, Innovate UK (cross-border payments prototype). Barclays, UBS and Credit Suisse are experimenting with Ethereum.
Ethereum-based permissioned blockchain variants are used and being investigated for various projects.
- J. P. Morgan Chase is developing JPM Coin on a permissioned-variant of Ethereum blockchain dubbed "Quorum". It's designed to toe the line between private and public in the realm of shuffling derivatives and payments. The idea is to satisfy regulators who need seamless access to financial goings-on, while protecting the privacy of parties that don't wish to reveal their identities nor the details of their transactions to the general public.
- Royal Bank of Scotland has announced that it has built a Clearing and Settlement Mechanism (CSM) based on the Ethereum distributed ledger and smart contract platform.
In Ethereum all smart contracts are stored publicly on every node of the blockchain, which has costs. Being a blockchain means it is secure by design and is an example of a distributed computing system with high Byzantine fault tolerance. The downside is that performance issues arise in that every node is calculating all the smart contracts in real time, resulting in lower speeds. As of January 2016, the Ethereum protocol could process about 25 transactions per second. In comparison, the Visa payment platform processes 45,000 payments per second leading some to question the scalability of Ethereum. On 19 December 2016, Ethereum exceeded one million transactions in a single day for the first time.
Ethereum's blockchain uses Merkle trees, for security reasons, to improve scalability, and to optimize transaction hashing. As with any Merkle tree implementation, it allows for storage savings, set membership proofs (called "Merkle proofs"), and light client synchronization. The Ethereum network has at times faced congestion problems, for example, congestion occurred during late 2017 in relation to Cryptokitties.
Development governance and EIP
Vlad Zamfir, Ethereum core developer, The New Yorker
In October 2015, a development governance was proposed as Ethereum Improvement Proposal, aka EIP, standardized on EIP-1. The core development group and community were to gain consensus by a process regulated EIP. A few notable decisions were made in the process of EIP, such as EIP-160 (EXP cost increase caused by Spurious Dragon Hardfork) and EIP-20 (ERC-20 Token Standard). In January 2018, the EIP process was finalized and published as EIP-1 status turned "active". Alongside ERC-20, notable EIPs to have become finalised token standards include ERC-721 (enabling the creation of non-fungible tokens, as used in Cryptokitties) and as of June 2019, ERC-1155  (enabling the creation of both fungible and non-fungible tokens within a single smart contract with reduced gas costs).
Izabella Kaminska, the editor of FT Alphaville, has pointed out that criminals are using Ethereum to run Ponzi schemes and other forms of investment fraud. The article was based on a paper from the University of Cagliari, which placed the number of Ethereum smart contracts which facilitate Ponzi schemes at nearly 10% of 1384 smart contracts examined. However, it also estimated that only 0.05% of the transactions on the network were related to such contracts.
- "ethereum". GitHub. Retrieved 11 January 2018.
- "Go Ethereum GitHub repository". Archived from the original on 3 October 2016.
- Cryptocurrencies: A Brief Thematic Review Archived 25 December 2017 at the Wayback Machine. Social Science Research Network. Date accessed 28 August 2017.
- Tapscott, Don; Tapscott, Alex (7 May 2016). The Blockchain Revolution: How the Technology Behind Bitcoin is Changing Money, Business, and the World. Portfolio. ISBN 978-0670069972.
- "Ethereum Block Explorer - Supply and Market Capitalization". Archived from the original on 24 April 2019.
- Waters, Richard (18 June 2016). "'Ether' brought to earth by theft of $50m in cryptocurrency". ft.com. The 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.
- 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.
- Paumgarten, Nick (22 October 2018). "The Prophets of Cryptocurrency Survey the Boom and Bust". The New Yorker. Retrieved 4 February 2019.
- "White Paper· ethereum/wiki Wiki · GitHub". Archived from the original on 11 January 2014.
- Finley, Klint (27 January 2014). "Out in the Open: Teenage Hacker Transforms Web Into One Giant Bitcoin Network". Wired. Archived from the original on 18 March 2016. Retrieved 21 March 2016.
- Schneider, Nathan (7 April 2014). "Code your own utopia: Meet Ethereum, bitcoin's most ambitious successor". Al Jazeera. Archived from the original on 23 February 2016. Retrieved 21 February 2016.
- Schmid, Valentin (10 May 2014). "The Entrepreneur: Joe Lubin, COO of Ethereum". Epoch Times. Archived from the original on 25 April 2016. Retrieved 31 March 2016.
- "Company Overview of Ethereum Switzerland GmbH". Bloomberg. 20 August 2016. Archived from the original on 20 August 2016. Retrieved 20 August 2016.
The company was founded in 2014 and is based in Baar, Switzerland.
- Dannen, Chris (16 March 2017). Introducing Ethereum and Solidity: Foundations of Cryptocurrency and Blockchain Programming for Beginners. Apress. p. 30. ISBN 9781484225356. Retrieved 12 November 2018.
- Popper, Nathaniel (27 February 2017). "Business Giants to Announce Creation of a Computing System Based on Ethereum". New York Times. Archived from the original on 20 June 2017. Retrieved 5 June 2017.
- Peck, Morgan (2 March 2017). "Corporate Titans Unite to Build an Enterprise Version of the Ethereum Blockchain". Institute of Electrical and Electronics Engineers (IEEE). Archived from the original on 17 June 2017. Retrieved 5 June 2017.
- "Enterprise Ethereum Alliance expands dramatically announcing 86 new members" (PDF) (Press release). Enterprise Ethereum Alliance (EEA). 19 May 2017. Archived (PDF) from the original on 7 June 2017. Retrieved 5 June 2017.
- Shin, Laura (22 May 2017). "Ethereum Enterprise Alliance Adds 86 New Members Including DTCC, State Street And Infosys". Forbes. Archived from the original on 22 May 2017. Retrieved 22 May 2017.
- "The Enterprise Ethereum Alliance Just Got A Whole Lot Stronger".
- "Sberbank joins Enterprise Ethereum Alliance to broaden cooperation"(19 Oct 2017). Fintech Futures News. Retrieved 6 June 2018.
- Vigna, Paul (31 July 2015). "BitBeat: Ethereum Opens Its 'Frontier' for Business". The Wall Street Journal. Archived from the original on 6 September 2017. Retrieved 5 June 2017.
- Gupta, Vinay (3 March 2015). "The Ethereum Launch Process". Ethereum Foundation. Archived from the original on 6 June 2017. Retrieved 5 June 2017.
- Vigna, Paul (16 May 2016). "Chiefless Company Rakes in More than $100 Million". Wall Street Journal. Archived from the original on 25 June 2017. Retrieved 14 May 2017.
- Popper, Nathaniel (18 June 2016). "Hacker May Have Taken $50 Million From Cybercurrency Project". The New York Times. Archived from the original on 20 June 2017. Retrieved 14 May 2017.
- Price, Rob (17 June 2016). "Digital Currency Ethereum is Cratering Amid Claims of a $50 Million Hack". Business Insider. Business Insider. Archived from the original on 11 June 2017. Retrieved 14 May 2017.
- Peck, Morgan (19 July 2016). ""Hard Fork" Coming to Restore Ethereum Funds to Investors of Hacked DAO". IEEE Spectrum: Technology, Engineering, and Science News. IEEE. Archived from the original on 3 March 2017. Retrieved 14 May 2017.
- Leising, Matthew (13 June 2017). "The Ether Thief". www.bloomberg.com. Retrieved 21 December 2018.
- "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.
- Varshney, Neer (11 June 2018). "Ethereum's supply has crossed 100M, here's what that means". Hard Fork | The Next Web. Retrieved 25 May 2019.
- Olga Kharif (11 October 2017). "Fans of Digital Currency Ether Can Now Buy ETNs—In Sweden". Bloomberg.
- Triantafyllidis, Nikolaos Petros (19 February 2016). "The Ethereum Project: Ethereum History". Developing an Ethereum Blockchain Application (Report). University of Amsterdam. p. 20.
- "ethernodes.org - The Network number 1". ethernodes.org. Retrieved 1 February 2018.
- Piasecki, Piotr J. (2016). "Gaming Self-Contained Provably Fair Smart Contract Casinos". Ledger. 1: 99–110. doi:10.5195/ledger.2016.29. Archived from the original on 24 December 2016.
- Peck, M. (28 May 2016). "Ethereum's $150-Million Blockchain-Powered Fund Opens Just as Researchers Call For a Halt". IEEE Spectrum. Institute of Electrical and Electronics Engineers. Archived from the original on 30 May 2016.
- "Short Paper: Formal Verification of Smart Contracts" (PDF). microsoft.com/. Microsoft. Archived from the original (PDF) on 27 August 2016. Retrieved 25 August 2016.
- "Ethereum vs. Bitcoin" (PDF). Economist. 20 August 2018.
- "Bitcoin Vs Ethereum: Driven by Different Purposes". Investopedia. 20 August 2018.
- "Litecoin vs. Ethereum". 20 August 2018.
- "This Is Your Company on Blockchain". Bloomberg Businessweek. Archived from the original on 14 September 2016. Retrieved 14 September 2016.
- "Big Business Giants From Microsoft to J.P. Morgan Are Getting Behind Ethereum". Fortune. Archived from the original on 29 September 2017. Retrieved 8 November 2017.
- "Hyperledger blockchain code almost comes together for IoT". Rethink Research. Archived from the original on 16 August 2016. Retrieved 23 April 2016.
- Allison, Ian (3 May 2016). "Deloitte to build Ethereum-based 'digital bank' with New York City's ConsenSys". International Business Times. Archived from the original on 6 May 2016.
- Allison, Ian (20 January 2016). "R3 connects 11 banks to distributed ledger using Ethereum and Microsoft Azure". International Business Times. Archived from the original on 23 February 2016. Retrieved 23 February 2016.
- "Settlement using blockchain to Automate Foreign Exchange in a Regulated environment (SAFER)". Innovate UK. Archived from the original on 4 May 2016.
- "JP Morgan's Quorum blockchain powers new correspondent banking network " Banking Technology". www.bankingtech.com. Archived from the original on 9 November 2017. Retrieved 8 November 2017.
- Hacket, Robert. "Why J.P. Morgan Chase Is Building a Blockchain on Ethereum". Fortune. Archived from the original on 2 February 2017.
- "Proving Ethereum for the Clearing Use Case" (PDF). Archived (PDF) from the original on 10 October 2016.
- Allison, Ian (7 December 2016). "Blockchain: RBS builds Ethereum-based distributed clearing house". IB Times. Archived from the original on 13 April 2017. Retrieved 8 May 2017.
- Allison, Ian (25 January 2016). "How are banks actually going to use blockchains and smart contracts?". International Business Times. Archived from the original on 8 May 2016. Retrieved 4 May 2016.
- Murphy, Hannah (19 October 2018). "The rise and fall of Ethereum". Financial Times. London: The Financial Times Ltd. Retrieved 19 October 2018.
- Filiba, Jack. "Ethereum Breaks One Million Transactions in a Single Day". Archived from the original on 22 December 2017.
- Galeon, Dom. "Ethereum's Co-Founder Just Unveiled His Plan for the Future of Cryptocurrency". Archived from the original on 9 November 2017.
- Vitalik Buterin. "Merkling in Ethereum". Ethereum.org.
- Joon Ian Wong. "The ethereum network is getting jammed up because people are rushing to buy cartoon cats on its blockchain". QZ.com.
- "Update status EIP-1 according to own specification · ethereum/EIPs@db14da1". GitHub. Retrieved 2 July 2018.
- Becze, Martin; Jameson, Hudson. "Ethereum EIP-1 on Github". GitHub. Retrieved 2 July 2018.
- Vitalik, Buterin. "Ethereum EIP-160 EXP cost increase". GitHub. Retrieved 2 July 2018.
- "Ethereum EIP-20:ERC-20 Token Standard". GitHub. Retrieved 2 July 2018.
- "ERC: Non-fungible Token Standard · Issue #721 · ethereum/EIPs". GitHub. Retrieved 29 July 2019.
- June 17, Jordan Heal; 2019 507 (17 June 2019). "Ethereum adopts ERC-1155 as an official standard". Coin Rivet. Retrieved 29 July 2019.
- Kaminska, Izabella (1 June 2017). "It's not a ponzi, it's a smart ponzi". FT Alphaville. Archived from the original on 23 July 2017.
- Bartoletti, Carta; et al. (2017). "Dissecting Ponzi schemes on Ethereum: identification, analysis, and impact". Universita di Cagliari. arXiv:1703.03779. Bibcode:2017arXiv170303779B. Cite journal requires
|Wikimedia Commons has media related to Ethereum.|