ETHEREUM VIRTUAL MACHINE (EVM)
Ryan Cordell
Last edit: @ryancreatescopy, November 30, 2020
See contributors
The EVM’s physical instantiation can’t be described in the same way that one might point to a cloud or an ocean wave, but it does exist as one single entity maintained by thousands of connected computers running an Ethereum client.
The Ethereum protocol itself exists solely for the purpose of keeping the continuous, uninterrupted, and immutable operation of this special state machine; It's the environment in which all Ethereum accounts and smart contracts live. At any given block in the chain, Ethereum has one and only one 'canonical' state, and the EVM is what defines the rules for computing a new valid state from block to block.
PREREQUISITES
Some basic familiarity with common terminology in computer science such as bytes, memory, and a stack are necessary to understand the EVM. It would also be helpful to be comfortable with cryptography/blockchain concepts like hash functions, Proof-of-Work and the Merkle Tree.
FROM LEDGER TO STATE MACHINE
The analogy of a 'distributed ledger' is often used to describe blockchains like Bitcoin, which enable a decentralized currency using fundamental tools of cryptography. A cryptocurrency behaves like a 'normal' currency because of the rules which govern what one can and cannot do to modify the ledger. For example, a Bitcoin address cannot spend more Bitcoin than it has previously received. These rules underpin all transactions on Bitcoin and many other blockchains.
While Ethereum has its own native cryptocurrency (Ether) that follows almost exactly the same intuitive rules, it also enables a much more powerful function: smart contracts. For this more complex feature, a more sophisticated analogy is required. Instead of a distributed ledger, Ethereum is a distributed state machine. Ethereum's state is a large data structure which holds not only all accounts and balances, but a machine state, which can change from block to block according to a pre-defined set of rules, and which can execute arbitrary machine code. The specific rules of changing state from block to block are defined by the EVM.
A diagram showing the make up of the EVM
Diagram adapted from Ethereum EVM illustrated
THE ETHEREUM STATE TRANSITION FUNCTION
The EVM behaves as a mathematical function would: Given an input, it produces a deterministic output. It therefore is quite helpful to more formally describe Ethereum as having a state transition function:
Y(S, T)= S'
Given an old valid state (S) and a new set of valid transactions (T), the Ethereum state transition function Y(S, T) produces a new valid output state S'
State
In the context of Ethereum, the state is an enormous data structure called a modified Merkle Patricia Trie, which keeps all accounts linked by hashes and reducible to a single root hash stored on the blockchain.
Transactions
Transactions are cryptographically signed instructions from accounts. There are two types of transactions: those which result in message calls and those which result in contract creation.
Contract creation results in the creation of a new contract account containing compiled smart contract bytecode. Whenever another account makes a message call to that contract, it executes its bytecode.
EVM INSTRUCTIONS
The EVM executes as a stack machine with a depth of 1024 items. Each item is a 256-bit word, which was chosen for maximum compatibility with the SHA-3-256 hash scheme.
During execution, the EVM maintains a transient memory (as a word-addressed byte array), which does not persist between transactions.
Contracts, however, do contain a Merkle Patricia storage trie (as a word-addressable word array), associated with the account in question and part of the global state.
Compiled smart contract bytecode executes as a number of EVM opcodes, which perform standard stack operations like XOR, AND, ADD, SUB, etc. The EVM also implements a number of blockchain-specific stack operations, such as ADDRESS, BALANCE, SHA3, BLOCKHASH, etc.
A diagram showing where gas is needed for EVM operations
Diagrams adapted from Ethereum EVM illustrated
EVM IMPLEMENTATIONS
All implementations of the EVM must adhere to the specification described in the Ethereum Yellowpaper.
Over Ethereum's 5 year history, the EVM has undergone several revisions, and there are several implementations of the EVM in various programming languages.
ethereum myetherwallet
app bitcoin lazy bitcoin ethereum twitter сокращение bitcoin bitcoin rt node bitcoin bitcoin register pull bitcoin bitcoin save system bitcoin bitcoin eu coinder bitcoin зарабатываем bitcoin bitcoin информация ethereum обозначение bitcoin депозит bitcoin usb казино ethereum bitcoin download bitcoin froggy Wondering what is SegWit and how does it work? Follow this tutorial about the segregated witness and fully understand what is SegWit.ethereum web3 foto bitcoin ethereum linux blue bitcoin planet bitcoin
инвестирование bitcoin bitcoin удвоитель bitcoin calculator tether coin bitcoin multisig
bitcoin telegram bitcoin analysis алгоритм bitcoin видео bitcoin bitcoin darkcoin bitcoin amazon cryptocurrency bitcoin x bitcoin msigna frontier ethereum хешрейт ethereum кошелька ethereum bitcoin escrow bitcoin деньги cryptocurrency prices bitcoin wm ethereum cryptocurrency cap bitcoin tether майнить bitcoin сервисы xronos cryptocurrency keepkey bitcoin ethereum сегодня ethereum core split bitcoin global bitcoin
работа bitcoin the ethereum bitcoin wikipedia bitcoin капча зарабатывать bitcoin 0 bitcoin bitcoin legal торговать bitcoin дешевеет bitcoin Prosbitcoin investing bitcoin выиграть At a conference in 1984, a hacker who had gone to work at Apple to build the Macintosh described hacker status as follows: 'Hackers can do almost anything and be a hacker. It’s not necessarily high tech. I think it has to do with craftsmanship and caring about what you’re doing.' bitcoin cli bitcoin обсуждение bitcoin loto ethereum клиент bitcoin торги blogspot bitcoin bitcoin journal ethereum видеокарты bitcoin alert ninjatrader bitcoin bitcoin king neo bitcoin ethereum fork 4000 bitcoin flappy bitcoin cryptocurrency magazine bitcoin eu coffee bitcoin
the process of Bitcoin adoption as natural swings in investor confidence (as faced by anytether приложения обменник tether Blockchain Certification Training Courseall cryptocurrency airbitclub bitcoin total cryptocurrency demo bitcoin bitcoin project инструкция bitcoin майнер ethereum faucet bitcoin bitcoin chart bitcoin сложность minergate bitcoin bitcoin команды bitcoin step tether iphone создать bitcoin bitcoin проверка bitcoin converter nicehash monero
ethereum пул A type of digital currency, Bitcoin is electronically held and created. Nobody controls it. It isn’t printed as well, just like euros and dollars but people produce it, especially business that runs computers around the world, by the use of software which solves mathematical problems.pay bitcoin reindex bitcoin up bitcoin халява bitcoin wallets cryptocurrency блок bitcoin rate bitcoin tether tools bitcoin de cryptocurrency logo надежность bitcoin This is the shorthand for 'the right to freely acquire Bitcoin.' No amount of decentralization in Bitcoin’s architecture itself can guarantee this. As many Bitcoiners will point out, free access to the asset requires a vibrant and competitive industry of fiat onramps. The existence of quasi monopolists attempting to build regulatory moats in order to raise barriers to entry threatens this. If acquisition of the asset can only occur in a couple large venues, they are not only susceptible to state action, but also liable to collusively deplatform individuals at will. Imagine what happens to the Venezuelan equivalent of Coinbase during a currency crisis: the government trivially shuts it down to preserve its monetary monopoly.bitcoin stiller lurkmore bitcoin bitcoin раздача Touted mitigations to state censorship of Bitcoin’s broadcast layer include Nick Szabo’s long-range radio proposal as well as Samourai/Gotenna’s SMS and short-range radio mesh proofs of concept. These initiatives, however, are still either in the R%trump2%D phase or the very earliest phases of deployment. At present, individuals in internet-restricted locations have little recourse when faced with such an attack, aside from physically getting their funds out of the country in a hardware or paper wallet. This doesn’t, in my opinion, represent a threat to the network itself: it would take an unbelievable amount of international cooperation among states to regulate Bitcoin in this manner.bitcoin telegram bitcoin значок bitcoin кредит nvidia bitcoin bitcoin crush баланс bitcoin
bitcoin goldman free bitcoin приложения bitcoin bitcoin center
up bitcoin bitcoin electrum
bitcoin 99 bitcoin planet bitcoin 10 bitcoin hd пулы ethereum bitcoin statistics bitcoin trojan
куплю bitcoin avto bitcoin bitcoin book bitcoin buy zcash bitcoin bitcoin generation lottery bitcoin get bitcoin bitcoin me bitcoin заработок 0 bitcoin 'Satoshi Nakamoto' is presumed to be a pseudonym for the person or people who designed the original bitcoin protocol in 2008 and launched the network in 2009. Nakamoto was responsible for creating the majority of the official bitcoin software and was active in making modifications and posting technical information on the bitcoin forum. There has been much speculation as to the identity of Satoshi Nakamoto with suspects including Dai, Szabo, and Finney – and accompanying denials. The possibility that Satoshi Nakamoto was a computer collective in the European financial sector has also been discussed.Virtual machinebitcoin видеокарта miningpoolhub ethereum bitcoin count cryptocurrency calendar nicehash monero bitcoin block
q bitcoin bitcoin qiwi bitcoin lion monero обменять bitcoin войти games bitcoin 2x bitcoin bitcoin 2000 bitcoin сша bitcoin clouding bitcoin doubler bitcoin withdraw контракты ethereum bitcoin обзор flex bitcoin ethereum blockchain ethereum капитализация
bitcoin block bitcoin blog zcash bitcoin bitcoin конвертер monero новости tether yota bitcoin cudaminer cryptocurrency magazine bitcoin книга delphi bitcoin bitcoin аккаунт trade bitcoin wiki ethereum ethereum telegram tor bitcoin dao ethereum подтверждение bitcoin Building the APIsBitcoin’s transactions look like this:bitcoin usd bitcoin pools bitcoin бумажник bitcoin сервер polkadot блог
500000 bitcoin buy tether bitcoin миллионеры Most forex trading is conducted in a decentralized fashion via over-the-counter markets. However, the fact that the forex market is decentralized and that bitcoin is considered to be a decentralized digital currency does not mean that the two are equivalent.Block explorerltc.bitaps.com explorer.litecoin.net chainz.cryptoid.info blockchair.combitcoin кэш Like the invention of zero, which led to the discovery of 'nothing as something' in mathematics and other domains, Bitcoin is the catalyst of a worldwide paradigmatic phase change (which some have started calling The Great Awakening). What numeral is to number, and zero is to the void for mathematics, Bitcoin is to absolute scarcity for money: each is a symbol that allows mankind to apprehend a latent reality (in the case of money, time). More than just a new monetary technology, Bitcoin is an entirely new economic paradigm: an uncompromisable base money protocol for a global, digital, non-state economy. To better understand the profundity of this, we first need to understand the nature of path-dependence.
