• Development status Active Written in,, Clients available for,,,, x86, AMD64, ARM,,, 3, Website Ethereum is an, public, -based platform and featuring (scripting) functionality. It supports a modified version of Nakamoto consensus via transaction based state transitions. Along with, Ethereum is considered to be one of the pioneer platforms in and technology. [ ] Ether is a whose blockchain is generated by the Ethereum platform. Ether can be transferred between accounts and used to compensate participant mining nodes for computations performed. Ethereum provides a decentralized, the Ethereum Virtual Machine (EVM), which can execute scripts using an international network of public nodes. F2pool Monero XMR Mining Pool here.

'Gas', an internal transaction pricing mechanism, is used to mitigate and allocate resources on the network. Ethereum was proposed in late 2013 by, a researcher and programmer. Development was funded by an online that took place between July and August 2014. The system went live on 30 July 2015, with 11.9 million coins 'premined' for the crowdsale.

This accounts for approximately 13 percent of the total circulating supply. In 2016, as a result of the collapse of project, Ethereum was split into two separate blockchains – the new separate version became Ethereum (ETH), and the original continued as (ETC). The value of the Ethereum currency grew over 13,000 percent in 2017. Vitalik Buterin at in 2015. Ethereum was initially described in a white paper by, a programmer involved with, in late 2013 with a goal of building decentralized applications. Buterin had argued that Bitcoin needed a for application development. Failing to gain agreement, he proposed development of a new platform with a more general scripting language.: 88 At the time of public announcement in January 2014, the core Ethereum team was Vitalik Buterin, Mihai Alisie, Anthony Di Iorio, and Charles Hoskinson.

Formal development of the Ethereum software project began in early 2014 through a company, ( EthSuisse). Subsequently, a Swiss non-profit foundation, the Ethereum Foundation ( Stiftung Ethereum), was created as well. Development was funded by an online public during July–August 2014, with the participants buying the Ethereum value token (ether) with another digital currency,. 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,,,,,,,,,,,,,,,, and. By July 2017, there were over 150 members in the alliance, including recent additions,, and.

Milestones [ ] Version Code name Release date Old version, no longer supported: 0 Olympic May, 2015 Old version, no longer supported: 1 Frontier 30 July 2015 Old version, no longer supported: 2 Homestead 14 March 2016 Current stable version: 3 Metropolis (vByzantium) 16 October 2017 Future release: 3.5 Metropolis (vConstantinople) TBA Future release: 4 Serenity TBA. 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 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. 'Homestead' was the first to be considered.

Ethereum Classic is an open-source, public, blockchain-based distributed computing platform featuring smart contract (scripting) functionality. It provides a. With the current high exchange rate of Ethereum Classic (ETC) it is proving to be more profitable to mine and sell by cryptos.

It includes improvements to transaction processing, gas pricing, and security. Since the initial launch, Ethereum has undergone several planned protocol upgrades, which are important changes affecting the underlying functionality and/or of the platform.

There are at least two other protocol upgrades planned in the future: 'Metropolis' is intended to reduce the complexity of the EVM and provide more flexibility for smart contract developers. Metropolis also adds supports for zkSnarks (from ); with the first zksnarks transaction occurring on testnet on September 19, 2017. 'Serenity' should include a fundamental change to Ethereum's consensus algorithm to enable a basic transition from hardware mining () to virtual mining (). Improvements to, specifically, are also said to be a key objective on the development roadmap. The DAO event [ ] In 2016 a called, a set of developed on the platform, raised a record US$150 million in a to fund the project.

The DAO was exploited in June when US$50 million in ether were claimed by an anonymous entity. 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 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 protection, de-bloated the blockchain, and thwarted further spam attacks by hackers. Further information: As with other cryptocurrencies, the validity of each ether is provided by a, which is a continuously growing list of, called blocks, which are linked and secured using. By design, the blockchain is inherently resistant to modification of the data. It is an open, that records transactions between two parties efficiently and in a verifiable and permanent way. A stores the or 'addresses' which can be used to receive or spend Ether.

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 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.

Owners can store these addresses in software, on paper and possibly in memory ('brain wallet'). Addresses [ ] Ethereum addresses are composed of the prefix '0x', a common identifier for, concatenated with the rightmost 20 bytes of the hash () of the. In hexadecimal, 2 digits represents a byte, meaning addresses contain 40 hexadecimal digits. One example is 0xb794f5ea0ba39494ce839613fffba8, the Poloniex ColdWallet.

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 to ensure that addresses are properly typed. Comparison to bitcoin [ ] Ether is different from (the with the largest as of January 2018) in several aspects: • Its is 14 to 15 seconds, compared with 10 minutes for bitcoin. • of ether generates new coins at a usually consistent rate, occasionally changing during hard forks, while for bitcoin the rate halves every 4 years. • 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 gas units each have a price that can be specified in a transaction. This is typically measured in Gwei. Bitcoin transactions usually have fees specified in satoshis per byte.

• Transaction fees are generally considerably lower for ether than for Bitcoin. In December 2017, the median transaction fee for ether corresponded to $0.33, while for bitcoin it corresponded to $23. • 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. Both systems have their pros and cons; in terms of storage space, complexity, and security/anonymity. • Ethereum is planned to transfer to full, currently it is a hybrid between Proof-of-Work and Proof-of-Stake. This scheme is commonly known as Casper Friendly Finality Gadget (FFG), whereas the pure Proof-of-Stake system is known as Casper Correct-by-Construction (CBC).

Mining becomes obsolete during Casper CBC, via an exponential difficulty bomb in Ethash. Cryptocurrency as of 27 January 2018, in billions of. The total supply of ether was Ξ98 million as of January 2018. 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, but it is expected to end at a certain point, and become deflationary. Markets and stores [ ] Ether can be traded by regular currency,, as well as many online.

As of January 2018, at least 150 stores accept ether. Platform [ ] Virtual Machine [ ] The Ethereum Virtual Machine (EVM) is the runtime environment for smart contracts in Ethereum. It is a 256-bit register stack, designed to run the same code exactly as intended. It is the fundamental consensus mechanism for Ethereum. The formal definition of the EVM is specified in the Ethereum Yellow Paper.

It is sandboxed and also completely isolated from the network, filesystem or other processes of the host computer system. Every Ethereum node in the network runs an EVM implementation and executes the same instructions. In February 1, 2018, there were 27,500 nodes in the main Ethereum network. Ethereum Virtual Machines have been implemented in,,,,,,,, and (currently under development). The Ethereum-flavoured WebAssembly (dubbed 'e-WASM') is expected to become a major component of the 'Web 3.0', a where smart contract and interact with users through a browser.

Smart contracts [ ] Ethereum's are based on computer language, which developers use to program their own functionalities. Smart contracts are programming that are compiled down to EVM and deployed to the Ethereum blockchain for execution. They can be written in (a language library with similarities to and ), Serpent (similar to, but deprecated), LLL (a -like language), and Mutan (-based, but deprecated). There is also a research-oriented language under development called Viper (a -derived ). Smart contracts can be public, which opens up the possibility to prove functionality, e.g. Self-contained casinos. 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 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. Applications [ ] Ethereum blockchain applications are usually referred to as DApps (), since they are based on the decentralized Ethereum Virtual Machine, and its smart contracts. Many uses have been proposed for Ethereum platform, including ones that are impossible or unfeasible. Use case proposals have included finance, the, produce,, and. Ethereum is (as of 2017) the leading platform for projects, with over 50% market share.

As of January 2018, there are more than 250 live DApps, with hundreds more under development. Project applications listed in this section are not exhaustive and may be outdated.

• that ensure authenticity and proof of existence of documents: the has developed such a system • Slock.It is developing • Digital tokens to: Dai, stablecoin pegged to US dollar. Decentralized Capital. Spanish bank is also involved in such a project. • Digital tokens to: Digix • Improved for music: used the technology • Platforms for:, Gnosis Stox • Platforms for: the DAO • Social media platforms with economic incentives: Backfeed, Akasha • Decentralized marketplaces: FreeMyVunk, Etheropt, TransActive Grid • Remittance: Everex • Online: CoinPoker, Etheroll • management: • Secure for the Internet: uPort •: Blocklancer, Ethlance •: popularity in December 2017 caused the Ethereum network to slow down. Enterprise software [ ] Ethereum-based customized software and networks, independent from the public Ethereum chain, are being tested by companies.

Interested parties include,,,,,, (cross-border payments prototype). Barclays, UBS and Credit Suisse are experimenting with Ethereum blockchain to automate Markets in Financial Instruments Directive (MiFID) II requirements. Permissioned ledgers [ ] Ethereum-based variants are used and being investigated for various projects.

• is developing 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. • has announced that it has built a Clearing and Settlement Mechanism (CSM) based on the Ethereum distributed ledger and smart contract platform.

Performance [ ] In Ethereum all smart contracts are stored publicly on every node of the blockchain, which has costs. Being a means it is and is an example of a distributed computing system with high. 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 25 transactions per second. On 19 December 2016, Ethereum exceeded one million transactions in a single day for the first time. • Micro Raiden was launched November 2017.

• Buterin and Joseph Poon (a co-author of 's lightning network whitepaper) announced in 2017 their plan to launch a scaling solution called Plasma which creates 'child' blockchains to the 'main' parent blockchain. The plasma project is not without skeptics, specifically Vlad Zamfir (Ethereum's lead researcher on proof of stake) has publicly questioned the plasma project's viability. • Ethereum engineers have been working on the calculations, and the next step (called Ethereum 2) was presented at Devcon 3. DigitalNote XDN Mining Pool Server Software on this page.

Ethereum's blockchain uses, 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. Criticisms [ ] A finance blogger on has pointed out that criminals are using Ethereum to run and other forms of investment fraud.

The article was based on a paper from the, 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. References [ ].