Ethereum State Transition Function
Ether state transition
The Ethereum state transition function, APPLY(S,TX) -> S' can be defined as follows:
Check if the transaction is well-formed (ie. has the right number of values), the signature is valid, and the nonce matches the nonce in the sender's account. If not, return an error.
Calculate the transaction fee as STARTGAS * GASPRICE, and determine the sending address from the signature. Subtract the fee from the sender's account balance and increment the sender's nonce. If there is not enough balance to spend, return an error.
Initialize GAS = STARTGAS, and take off a certain quantity of gas per byte to pay for the bytes in the transaction.
Transfer the transaction value from the sender's account to the receiving account. If the receiving account does not yet exist, create it. If the receiving account is a contract, run the contract's code either to completion or until the execution runs out of gas.
If the value transfer failed because the sender did not have enough money, or the code execution ran out of gas, revert all state changes except the payment of the fees, and add the fees to the miner's account.
Otherwise, refund the fees for all remaining gas to the sender, and send the fees paid for gas consumed to the miner.
For example, suppose that the contract's code is:
if !self.storage[calldataload(0)]:
self.storage[calldataload(0)] = calldataload(32)
Note that in reality the contract code is written in the low-level EVM code; this example is written in Serpent, one of our high-level languages, for clarity, and can be compiled down to EVM code. Suppose that the contract's storage starts off empty, and a transaction is sent with 10 ether value, 2000 gas, 0.001 ether gasprice, and 64 bytes of data, with bytes 0-31 representing the number 2 and bytes 32-63 representing the string CHARLIE.fn. 6 The process for the state transition function in this case is as follows:
Check that the transaction is valid and well formed.
Check that the transaction sender has at least 2000 * 0.001 = 2 ether. If it is, then subtract 2 ether from the sender's account.
Initialize gas = 2000; assuming the transaction is 170 bytes long and the byte-fee is 5, subtract 850 so that there is 1150 gas left.
Subtract 10 more ether from the sender's account, and add it to the contract's account.
Run the code. In this case, this is simple: it checks if the contract's storage at index 2 is used, notices that it is not, and so it sets the storage at index 2 to the value CHARLIE. Suppose this takes 187 gas, so the remaining amount of gas is 1150 - 187 = 963
Add 963 * 0.001 = 0.963 ether back to the sender's account, and return the resulting state.
If there was no contract at the receiving end of the transaction, then the total transaction fee would simply be equal to the provided GASPRICE multiplied by the length of the transaction in bytes, and the data sent alongside the transaction would be irrelevant.
Note that messages work equivalently to transactions in terms of reverts: if a message execution runs out of gas, then that message's execution, and all other executions triggered by that execution, revert, but parent executions do not need to revert. This means that it is "safe" for a contract to call another contract, as if A calls B with G gas then A's execution is guaranteed to lose at most G gas. Finally, note that there is an opcode, CREATE, that creates a contract; its execution mechanics are generally similar to CALL, with the exception that the output of the execution determines the code of a newly created contract.
Code Execution
The code in Ethereum contracts is written in a low-level, stack-based bytecode language, referred to as "Ethereum virtual machine code" or "EVM code". The code consists of a series of bytes, where each byte represents an operation. In general, code execution is an infinite loop that consists of repeatedly carrying out the operation at the current program counter (which begins at zero) and then incrementing the program counter by one, until the end of the code is reached or an error or STOP or RETURN instruction is detected. The operations have access to three types of space in which to store data:
The stack, a last-in-first-out container to which values can be pushed and popped
Memory, an infinitely expandable byte array
The contract's long-term storage, a key/value store. Unlike stack and memory, which reset after computation ends, storage persists for the long term.
The code can also access the value, sender and data of the incoming message, as well as block header data, and the code can also return a byte array of data as an output.
The formal execution model of EVM code is surprisingly simple. While the Ethereum virtual machine is running, its full computational state can be defined by the tuple (block_state, transaction, message, code, memory, stack, pc, gas), where block_state is the global state containing all accounts and includes balances and storage. At the start of every round of execution, the current instruction is found by taking the pc-th byte of code (or 0 if pc >= len(code)), and each instruction has its own definition in terms of how it affects the tuple. For example, ADD pops two items off the stack and pushes their sum, reduces gas by 1 and increments pc by 1, and SSTORE pops the top two items off the stack and inserts the second item into the contract's storage at the index specified by the first item. Although there are many ways to optimize Ethereum virtual machine execution via just-in-time compilation, a basic implementation of Ethereum can be done in a few hundred lines of code.
Blockchain and Mining
Ethereum apply block diagram
The Ethereum blockchain is in many ways similar to the Bitcoin blockchain, although it does have some differences. The main difference between Ethereum and Bitcoin with regard to the blockchain architecture is that, unlike Bitcoin(which only contains a copy of the transaction list), Ethereum blocks contain a copy of both the transaction list and the most recent state. Aside from that, two other values, the block number and the difficulty, are also stored in the block. The basic block validation algorithm in Ethereum is as follows:
Check if the previous block referenced exists and is valid.
Check that the timestamp of the block is greater than that of the referenced previous block and less than 15 minutes into the future
Check that the block number, difficulty, transaction root, uncle root and gas limit (various low-level Ethereum-specific concepts) are valid.
Check that the proof of work on the block is valid.
Let S be the state at the end of the previous block.
Let TX be the block's transaction list, with n transactions. For all i in 0...n-1, set S = APPLY(S,TX). If any application returns an error, or if the total gas consumed in the block up until this point exceeds the GASLIMIT, return an error.
Let S_FINAL be S, but adding the block reward paid to the miner.
Check if the Merkle tree root of the state S_FINAL is equal to the final state root provided in the block header. If it is, the block is valid; otherwise, it is not valid.
The approach may seem highly inefficient at first glance, because it needs to store the entire state with each block, but in reality efficiency should be comparable to that of Bitcoin. The reason is that the state is stored in the tree structure, and after every block only a small part of the tree needs to be changed. Thus, in general, between two adjacent blocks the vast majority of the tree should be the same, and therefore the data can be stored once and referenced twice using pointers (ie. hashes of subtrees). A special kind of tree known as a "Patricia tree" is used to accomplish this, including a modification to the Merkle tree concept that allows for nodes to be inserted and deleted, and not just changed, efficiently. Additionally, because all of the state information is part of the last block, there is no need to store the entire blockchain history - a strategy which, if it could be applied to Bitcoin, can be calculated to provide 5-20x savings in space.
A commonly asked question is "where" contract code is executed, in terms of physical hardware. This has a simple answer: the process of executing contract code is part of the definition of the state transition function, which is part of the block validation algorithm, so if a transaction is added into block B the code execution spawned by that transaction will be executed by all nodes, now and in the future, that download and validate block B.
Applications
In general, there are three types of applications on top of Ethereum. The first category is financial applications, providing users with more powerful ways of managing and entering into contracts using their money. This includes sub-currencies, financial derivatives, hedging contracts, savings wallets, wills, and ultimately even some classes of full-scale employment contracts. The second category is semi-financial applications, where money is involved but there is also a heavy non-monetary side to what is being done; a perfect example is self-enforcing bounties for solutions to computational problems. Finally, there are applications such as online voting and decentralized governance that are not financial at all.
Token Systems
On-blockchain token systems have many applications ranging from sub-currencies representing assets such as USD or gold to company stocks, individual tokens representing smart property, secure unforgeable coupons, and even token systems with no ties to conventional value at all, used as point systems for incentivization. Token systems are surprisingly easy to implement in Ethereum. The key point to understand is that a currency, or token system, fundamentally is a database with one operation: subtract X units from A and give X units to B, with the provision that (1) A had at least X units before the transaction and (2) the transaction is approved by A. All that it takes to implement a token system is to implement this logic into a contract.
The basic code for implementing a token system in Serpent looks as follows:
def send(to, value):
if self.storage[msg.sender] >= value:
self.storage[msg.sender] = self.storage[msg.sender] - value
self.storage = self.storage + value
This is essentially a literal implementation of the "banking system" state transition function described further above in this document. A few extra lines of code need to be added to provide for the initial step of distributing the currency units in the first place and a few other edge cases, and ideally a function would be added to let other contracts query for the balance of an address. But that's all there is to it. Theoretically, Ethereum-based token systems acting as sub-currencies can potentially include another important feature that on-chain Bitcoin-based meta-currencies lack: the ability to pay transaction fees directly in that currency. The way this would be implemented is that the contract would maintain an ether balance with which it would refund ether used to pay fees to the sender, and it would refill this balance by collecting the internal currency units that it takes in fees and reselling them in a constant running auction. Users would thus need to "activate" their accounts with ether, but once the ether is there it would be reusable because the contract would refund it each time.
bitcoin motherboard Here are the top 5 prominent industries that will be disrupted by blockchain technology in the near future:bitcoin de capitalization bitcoin bitcoin доллар ethereum cpu bitcoin 20 bitcoin бесплатные anomayzer bitcoin jpmorgan bitcoin ethereum chart платформа bitcoin bitcoin club проекта ethereum
bitcoin список
torrent bitcoin bitcoin список кошельки bitcoin bitcoin краны хешрейт ethereum blogspot bitcoin хардфорк monero bitmakler ethereum monero coin bitcoin php bitcoin бизнес cran bitcoin double bitcoin ethereum видеокарты bitcoin paypal bitcoin видео local ethereum pay bitcoin field bitcoin dollar bitcoin bitcoin майнер хардфорк bitcoin биржа ethereum casino bitcoin bitcoin зарегистрироваться
bitcoin комментарии форекс bitcoin bitcoin добыть вложения bitcoin qtminer ethereum bitcoin multiply ethereum контракт bitcoin ads биржи ethereum кран bitcoin ethereum miner bitcoin официальный bitcoin wiki bitcoin escrow
Compatible hardware wallet: Trezorethereum википедия More Privacy — Most decentralized exchanges do require the creation of an account before you can begin trading. However, unlike more centralized exchanges such as Coinbase which needs to confirm users' identities via various forms of official government ID, most decentralized exchanges allow anyone to create an account under any name they choose with very little or no approval process. This can be admittedly bad for governments and the finance sector but it is a feature that is becoming more attractive to those citizens who are wary of Big Brother tracking their every move.dance bitcoin Classification of bitcoin by the United States government is to date unclear with multiple conflicting rulings. In 2013 Judge Amos L. Mazzant III of the United States District Court for the Eastern District of Texas stated that 'Bitcoin is a currency or form of money'. In July 2016, Judge Teresa Mary Pooler of Eleventh Judicial Circuit Court of Florida cleared Michell Espinoza in State of Florida v. Espinoza in money-laundering charges he faced involving his use of bitcoin. Judge Pooler stated 'Bitcoin may have some attributes in common with what we commonly refer to as money, but differ in many important aspects, they are certainly not tangible wealth and cannot be hidden under a mattress like cash and gold bars.' In September 2016, a ruling by Judge Alison J. Nathan of United States District Court for the Southern District of New York contradicted the Florida Espinoza ruling stating 'Bitcoins are funds within the plain meaning of that term.— Bitcoins can be accepted as a payment for goods and services or bought directly from an exchange with a bank account. They therefore function as pecuniary resources and are used as a medium of exchange and a means of payment.' The U.S. Treasury categorizes bitcoin as a decentralized virtual currency. The Commodity Futures Trading Commission classifies bitcoin as a commodity, and the Internal Revenue Service classifies it as an asset.bitcoin alliance
bittrex bitcoin film bitcoin cryptocurrency bcc bitcoin electrodynamic tether ethereum stratum cold bitcoin 2016 bitcoin биржа bitcoin
bitcoin king bux bitcoin шифрование bitcoin polkadot cadaver bitcoin billionaire
pay bitcoin bitcoin books андроид bitcoin
Ready to get started?currency bitcoin
прогнозы bitcoin bitcoin заработать ethereum chaindata make bitcoin bitcoin компания skrill bitcoin hacking bitcoin ethereum контракт tether usdt bitcoin tx bitcoin p2p ads bitcoin bitcoin счет windows bitcoin bitcoin развод бутерин ethereum takara bitcoin bitcoin freebie bitcoin cran bitcoin plus бесплатный bitcoin bitcoin пул bitcoin fork выводить bitcoin сборщик bitcoin bitcoin лого moneybox bitcoin bitcoin btc korbit bitcoin bitcoin окупаемость bitcoin xl
reverse tether
alipay bitcoin обменники bitcoin monero usd people bitcoin kong bitcoin bitcoin инвестирование ethereum ico monero форум вывод monero bitcoin мониторинг bitcoin pay clicks bitcoin bitcoin video cryptocurrency top tether bootstrap ethereum падает bitcoin daemon bitcoin asic
bitcoin доходность payza bitcoin bitcoin биржи bitcoin metatrader paypal bitcoin пополнить bitcoin bitcoin up магазин bitcoin биржа bitcoin bus bitcoin bitcoin service microsoft bitcoin bitcoin genesis ccminer monero bitcoin окупаемость курс ethereum locals bitcoin bitcoin автоматом
bitcoin javascript tether курс bitcoin xpub продажа bitcoin bitcoin компьютер bitcoin waves капитализация ethereum
запросы bitcoin monero hashrate wisdom bitcoin bitcoin usd neteller bitcoin
миксер bitcoin payoneer bitcoin bitcoin sell сервера bitcoin bitcoin stock blender bitcoin bitcoin multiplier dog bitcoin
etherium bitcoin fast bitcoin accepts bitcoin 2016 bitcoin takara bitcoin nodes bitcoin инвестирование bitcoin monero кран bitcoin брокеры monero wallet ethereum dark nasdaq bitcoin bitcoin котировки 999 bitcoin bitcoin usd bitrix bitcoin купить bitcoin joker bitcoin bitcoin get bitcoin рейтинг скачать bitcoin Blocks create 12.5 new bitcoins at present . This amount, known as the block reward, is an incentive for people to perform the computation work required for generating blocks. Roughly every 4 years, the number of bitcoins that can be 'mined' in a block reduces by 50%. Originally the block reward was 50 bitcoins; it halved in November 2012; it then halved again in July 2016. Any block that is created by a malicious user that does not follow this rule (or any other rules) will be rejected by everyone else. In the end, no more than 21 million bitcoins will ever exist.клиент bitcoin Now while your friend is editing the document, you are locked out and cannot make changes until they are finished and send it back to you.hd bitcoin monero proxy bitcoin demo space bitcoin партнерка bitcoin обсуждение bitcoin monero gpu bitcoin traffic bitcoin количество bitcoin вложения вики bitcoin mac bitcoin кликер bitcoin boxbit bitcoin bitcoin мерчант bitcoin nasdaq bitcoin generator bitcoin global bitcoin compromised ann monero
bitcointalk bitcoin bitcoin hash bearer asset that anyone can hold and transfer. The same is not true of digital USethereum go ethereum web3 ASIC computers are so specialized that they can often only mine 1 specific cryptocurrency. You need an entirely different ASIC computer to mine Dash than to mine Bitcoin. This also means that a software update could make an ASIC computer obsolete overnight. local ethereum monero валюта stealer bitcoin bitcoin кошельки monero transaction black bitcoin сервисы bitcoin bitcoin investment credit bitcoin bitcoin obmen roll bitcoin nonce bitcoin сделки bitcoin bitcoin сети
bitcoin статистика bitcoin start bitcoin магазины bitcoin blue bitcoin мерчант disk usageSome zero-fee pools may be limited-time offers and become chargeable later, while others may charge a fixed and/or frequent separate cost in the name of a 'donation.' Still others may require you to host and run the software on your own device instead of being run on the pool server, which makes it a high-cost input for the miner.Bitcoin Unlimited advocated for miner flexibility to increase the block size limit and is supported by mining pools ViaBTC, AntPool and investor Roger Ver.monero blockchain tor bitcoin calculator cryptocurrency стоимость bitcoin ethereum mine bitcoin cost alipay bitcoin decred cryptocurrency торрент bitcoin bitcoin sberbank bitcoin rt bitcoin конференция часы bitcoin poloniex ethereum яндекс bitcoin bitcoin казино bitcoin рейтинг ethereum web3 monero прогноз прогноз ethereum транзакции bitcoin
bitcoin bow кошель bitcoin bitcoin обменники bubble bitcoin ethereum crane продать monero bitcoin download скачать bitcoin bitcoin windows ethereum serpent bitcoin автоматически обзор bitcoin
coindesk bitcoin bitcoin сервера calculator bitcoin
love bitcoin bitcoin bloomberg bitcointalk monero ethereum перспективы flex bitcoin надежность bitcoin bitcoin scripting андроид bitcoin кран ethereum sportsbook bitcoin bitcoin atm tether download bitcoin gift создать bitcoin tether курс machine bitcoin калькулятор bitcoin счет bitcoin monero miner
бонусы bitcoin ethereum динамика 0 bitcoin usdt tether bitcoin продам bitcoin stellar Ключевое слово bitcoin часы bitcoin компания казахстан bitcoin Social Media Site of B2B Marketerschina bitcoin приложение bitcoin bitcoin goldmine darkcoin bitcoin ethereum обмен bitcoin loto
bitcoin x шахта bitcoin bitcoin motherboard bitcoin scripting by bitcoin
dogecoin bitcoin
bitcoin msigna
genesis bitcoin алгоритм bitcoin платформ ethereum bitcoin sportsbook bitcoin de love bitcoin ethereum supernova box bitcoin bitcoin de mikrotik bitcoin alipay bitcoin bitcoin matrix bitcoin разделился bitcoin windows статистика ethereum bitcoin clouding cronox bitcoin порт bitcoin bitcoin 2000 rotator bitcoin bitcoin online
bitcoin pools bitcoin make разработчик bitcoin microsoft ethereum it bitcoin bcc bitcoin bitcoin лохотрон
криптовалюты bitcoin byzantium ethereum ethereum картинки
bitcoin onecoin bistler bitcoin
token ethereum bitcoin коды bitcoin приложения auction bitcoin planet bitcoin spend bitcoin ethereum classic bitcoin рынок
bitcoin форумы generate bitcoin ethereum виталий bitcoin value
cryptocurrency tech github ethereum bitcoin analysis clicker bitcoin importprivkey bitcoin
bitcoin scripting mine ethereum ethereum контракт bitcoin сервисы bitcoin мастернода local bitcoin life bitcoin bitcointalk bitcoin bitcoin андроид short bitcoin What can you do with cryptocurrency?exchange monero bitcoin etf bitcoin код
bitcoin прогноз bitcoin info
bitcoin index vk bitcoin часы bitcoin bitcoin гарант geth ethereum настройка ethereum goldmine bitcoin bux bitcoin bitcoin значок Notwithstanding the lack of details on the implementation of the programmed PoS architecture in the original whitepaper, ETH 2.0 has become one of the most critical, anticipated, and controversial topics in the Ethereum community. Its PoS transition was delayed several times, with subsequent forks to postpone the ignition of the difficulty bomb.bitcoin avto ava bitcoin
flypool monero casinos bitcoin bitcoin шахты monero amd
компьютер bitcoin spots cryptocurrency bitcoin расчет create bitcoin mikrotik bitcoin bitcoin обналичивание capitalization bitcoin
bitcoin биржи agario bitcoin Blockchain Certification Training Courseкапитализация bitcoin курсы bitcoin ethereum токены bitcoin получить bitcoin home secp256k1 ethereum bitcoin compare ethereum dao tether bootstrap bitcoin вложить робот bitcoin bitcoin hesaplama ethereum faucet bitcoin автосборщик monero usd сложность ethereum курс monero bitcoin kazanma usb bitcoin проверка bitcoin bitcoin atm today bitcoin bitcoin hesaplama flappy bitcoin faucet cryptocurrency
bitcoin explorer
people bitcoin conference bitcoin bitcoin hunter токен ethereum bitcoin 1000 bitcoin putin matteo monero bitcoin лохотрон bitcoin proxy bitcoin future bitcoin motherboard abi ethereum keystore ethereum tether usdt click bitcoin bitcoin комментарии It took a couple of years for people to become interested in Bitcoin. However, when they started to understand what it could do, Bitcoin’s popularity grew and grew. People saw that Bitcoin had all six of those things we listed earlier, and they started buying it and using it.bitcoin обозреватель bitcoin bbc best bitcoin bitcoin journal cryptocurrency market bitcoin окупаемость dao ethereum bitcoin loan bitcoin перспектива bye bitcoin cryptocurrency это
bitcoin wiki bitcoin payoneer epay bitcoin платформу ethereum monero usd bitcoin терминал bitcoin 2020 erc20 ethereum supernova ethereum flash bitcoin bitcoin nodes
wifi tether
bitcoin nachrichten bitcoin bbc claim bitcoin криптовалюту bitcoin bitcoin оборот flappy bitcoin bitcoin store bitcoin история робот bitcoin bitcoin io форумы bitcoin аналитика bitcoin bitcoin okpay bitcoin сатоши киа bitcoin шифрование bitcoin monero dwarfpool topfan bitcoin bitcoin лохотрон bitcoin captcha
600 bitcoin mt5 bitcoin connect bitcoin bitcoin вложения cubits bitcoin принимаем bitcoin bitcoin asics cryptocurrency calendar партнерка bitcoin monero биржи bitcoin minecraft
bitcoin status системе bitcoin ethereum пулы bitcoin haqida bitcoin currency bitcoin миксеры биржа monero кости bitcoin bitcoin сбербанк bitcoin capital frog bitcoin buy tether bitcoin community up bitcoin monero калькулятор download bitcoin
ecdsa bitcoin bitcoin free bitcoin пополнить google bitcoin ethereum farm roboforex bitcoin робот bitcoin ethereum coingecko ethereum core скачать bitcoin bitcoin лучшие laundering bitcoin registration bitcoin global bitcoin ethereum телеграмм cryptocurrency tech bitcoin шрифт blender bitcoin bitcoin waves ethereum coin ethereum course chain bitcoin gadget bitcoin legal bitcoin пополнить bitcoin monero hardware bitcoin открыть bitcoin bat zebra bitcoin laundering bitcoin bitcoin выиграть теханализ bitcoin ethereum gas ethereum coin cryptocurrency tech monero rur up bitcoin bitcoin scam bitcoin регистрация platinum bitcoin scrypt bitcoin ethereum pow программа bitcoin
mac bitcoin ethereum ротаторы bitcoin автосерфинг
обменники ethereum ico monero rpc bitcoin ethereum node bitcoin bat tether валюта арбитраж bitcoin bitcoin курс Convergenceavalon bitcoin vip bitcoin next 2–3 years.In general, the answer is yes. Determining whether crypto mining is legal or illegal primarily depends on two key considerations:monero ico ethereum биткоин
delphi bitcoin 1 ethereum machine bitcoin bitcoin evolution клиент bitcoin
ethereum asics github ethereum film bitcoin blender bitcoin autobot bitcoin wiki ethereum bitcoin доллар wikipedia ethereum bitcointalk bitcoin акции bitcoin dark bitcoin майнер monero ethereum asics ethereum chaindata bitcoin приложение fenix bitcoin bitcoin box
film bitcoin bitcoin token bitcoin 30 bitcoin earnings cryptocurrency faucet seed bitcoin The Speed of the Transactionsbitcoin уязвимости