Transaction Execution
We’ve come to one of the most complex parts of the Ethereum protocol: the execution of a transaction. Say you send a transaction off into the Ethereum network to be processed. What happens to transition the state of Ethereum to include your transaction?
Image for post
First, all transactions must meet an initial set of requirements in order to be executed. These include:
The transaction must be a properly formatted RLP. “RLP” stands for “Recursive Length Prefix” and is a data format used to encode nested arrays of binary data. RLP is the format Ethereum uses to serialize objects.
Valid transaction signature.
Valid transaction nonce. Recall that the nonce of an account is the count of transactions sent from that account. To be valid, a transaction nonce must be equal to the sender account’s nonce.
The transaction’s gas limit must be equal to or greater than the intrinsic gas used by the transaction. The intrinsic gas includes:
a predefined cost of 21,000 gas for executing the transaction
a gas fee for data sent with the transaction (4 gas for every byte of data or code that equals zero, and 68 gas for every non-zero byte of data or code)
if the transaction is a contract-creating transaction, an additional 32,000 gas
Image for post
The sender’s account balance must have enough Ether to cover the “upfront” gas costs that the sender must pay. The calculation for the upfront gas cost is simple: First, the transaction’s gas limit is multiplied by the transaction’s gas price to determine the maximum gas cost. Then, this maximum cost is added to the total value being transferred from the sender to the recipient.
Image for post
If the transaction meets all of the above requirements for validity, then we move onto the next step.
First, we deduct the upfront cost of execution from the sender’s balance, and increase the nonce of the sender’s account by 1 to account for the current transaction. At this point, we can calculate the gas remaining as the total gas limit for the transaction minus the intrinsic gas used.
Image for post
Next, the transaction starts executing. Throughout the execution of a transaction, Ethereum keeps track of the “substate.” This substate is a way to record information accrued during the transaction that will be needed immediately after the transaction completes. Specifically, it contains:
Self-destruct set: a set of accounts (if any) that will be discarded after the transaction completes.
Log series: archived and indexable checkpoints of the virtual machine’s code execution.
Refund balance: the amount to be refunded to the sender account after the transaction. Remember how we mentioned that storage in Ethereum costs money, and that a sender is refunded for clearing up storage? Ethereum keeps track of this using a refund counter. The refund counter starts at zero and increments every time the contract deletes something in storage.
Next, the various computations required by the transaction are processed.
Once all the steps required by the transaction have been processed, and assuming there is no invalid state, the state is finalized by determining the amount of unused gas to be refunded to the sender. In addition to the unused gas, the sender is also refunded some allowance from the “refund balance” that we described above.
Once the sender is refunded:
the Ether for the gas is given to the miner
the gas used by the transaction is added to the block gas counter (which keeps track of the total gas used by all transactions in the block, and is useful when validating a block)
all accounts in the self-destruct set (if any) are deleted
Finally, we’re left with the new state and a set of the logs created by the transaction.
Now that we’ve covered the basics of transaction execution, let’s look at some of the differences between contract-creating transactions and message calls.
Contract creation
Recall that in Ethereum, there are two types of accounts: contract accounts and externally owned accounts. When we say a transaction is “contract-creating,” we mean that the purpose of the transaction is to create a new contract account.
In order to create a new contract account, we first declare the address of the new account using a special formula. Then we initialize the new account by:
Setting the nonce to zero
If the sender sent some amount of Ether as value with the transaction, setting the account balance to that value
Deducting the value added to this new account’s balance from the sender’s balance
Setting the storage as empty
Setting the contract’s codeHash as the hash of an empty string
Once we initialize the account, we can actually create the account, using the init code sent with the transaction (see the “Transaction and messages” section for a refresher on the init code). What happens during the execution of this init code is varied. Depending on the constructor of the contract, it might update the account’s storage, create other contract accounts, make other message calls, etc.
As the code to initialize a contract is executed, it uses gas. The transaction is not allowed to use up more gas than the remaining gas. If it does, the execution will hit an out-of-gas (OOG) exception and exit. If the transaction exits due to an out-of-gas exception, then the state is reverted to the point immediately prior to transaction. The sender is not refunded the gas that was spent before running out.
Boo hoo.
However, if the sender sent any Ether value with the transaction, the Ether value will be refunded even if the contract creation fails. Phew!
If the initialization code executes successfully, a final contract-creation cost is paid. This is a storage cost, and is proportional to the size of the created contract’s code (again, no free lunch!) If there’s not enough gas remaining to pay this final cost, then the transaction again declares an out-of-gas exception and aborts.
If all goes well and we make it this far without exceptions, then any remaining unused gas is refunded to the original sender of the transaction, and the altered state is now allowed to persist!
Hooray!
Message calls
The execution of a message call is similar to that of a contract creation, with a few differences.
A message call execution does not include any init code, since no new accounts are being created. However, it can contain input data, if this data was provided by the transaction sender. Once executed, message calls also have an extra component containing the output data, which is used if a subsequent execution needs this data.
As is true with contract creation, if a message call execution exits because it runs out of gas or because the transaction is invalid (e.g. stack overflow, invalid jump destination, or invalid instruction), none of the gas used is refunded to the original caller. Instead, all of the remaining unused gas is consumed, and the state is reset to the point immediately prior to balance transfer.
Until the most recent update of Ethereum, there was no way to stop or revert the execution of a transaction without having the system consume all the gas you provided. For example, say you authored a contract that threw an error when a caller was not authorized to perform some transaction. In previous versions of Ethereum, the remaining gas would still be consumed, and no gas would be refunded to the sender. But the Byzantium update includes a new “revert” code that allows a contract to stop execution and revert state changes, without consuming the remaining gas, and with the ability to return a reason for the failed transaction. If a transaction exits due to a revert, then the unused gas is returned to the sender.
17. Name some leading open source platforms for developing Blockchain applications.advcash bitcoin bitcoin steam
bitcoin heist
bitcoin перевод ethereum обменники monero pro abi ethereum froggy bitcoin будущее bitcoin cardano cryptocurrency bitcoin legal bitcoin реклама bitcoin masters tether перевод monero fr bitcoin статистика стоимость bitcoin покер bitcoin cms bitcoin bitcoin пул bitcoin cc ethereum rub lurkmore bitcoin vps bitcoin bitcoin зарабатывать hardware bitcoin bux bitcoin пулы monero сложность ethereum gold cryptocurrency покер bitcoin котировки ethereum
bitcoin торговля msigna bitcoin weekend bitcoin
china bitcoin bitcoin habr bitcoin fees
трейдинг bitcoin bitcoin buying bitcoin cap get bitcoin криптовалюту monero cryptocurrency free bitcoin 4pda tether stellar cryptocurrency
bitcoin atm bitcoin home
bitcoin обменник bitcoin forum currency bitcoin and a precious metal assayer. To prevent fraud, each of the bookkeepers wasbitcoin xpub хардфорк ethereum bitcoin обмена clockworkmod tether заработка bitcoin
bitcoin genesis фонд ethereum bitcoin atm geth ethereum код bitcoin
продать monero tracker bitcoin криптовалюта monero amd bitcoin bitcoin транзакции
bitcoin зарегистрироваться cryptocurrency gold bitcoin 4096 код bitcoin сбербанк bitcoin видеокарты ethereum bitcoin plus500 bitcoin ubuntu bitcoin rotator
сервисы bitcoin программа ethereum bitcoin utopia konvert bitcoin
takara bitcoin
кран ethereum alliance bitcoin bitcoin payeer сборщик bitcoin бутерин ethereum difficulty ethereum bitcoin video bitcoin daily сети ethereum bitcoin casascius
tether верификация ethereum платформа программа ethereum bitcoin получение bitcoin gif ethereum продам bitcoin карта bitcoin rt bitcoin maining bitcoin p2p average bitcoin bitcoin eobot bitcoin валюта bitcoin click ethereum токены
магазины bitcoin алгоритм ethereum datadir bitcoin
clicks bitcoin bitcoin обменник ethereum ротаторы bistler bitcoin рынок bitcoin lootool bitcoin сложность monero обсуждение bitcoin bitcoin магазин algorithm bitcoin bitcoin blockstream bitcoin coinmarketcap
bitcoin daily proxy bitcoin эмиссия ethereum bitcoin fpga
халява bitcoin продать monero bitcoin asics bitcoin hosting instant bitcoin javascript bitcoin takara bitcoin Smart contracts are made possible by blockchains, a network of computers that work together to enforce rules on the network without requiring the help of an intermediary.twitter bitcoin бесплатно bitcoin bitcoin мошенники сеть ethereum
bitcoin betting bitcoin motherboard ethereum chart cryptocurrency calendar арбитраж bitcoin cpuminer monero block ethereum faith in a mathematical framework that is free of politics and human error.'16bitcoin statistics шахта bitcoin abc bitcoin куплю ethereum miningpoolhub ethereum bitcoin haqida bitcoin skrill armory bitcoin node bitcoin валюта tether half bitcoin и bitcoin bitcoin grafik купить ethereum
bitcoin trinity multi bitcoin mastering bitcoin bitcoin galaxy java bitcoin bitcoin earnings
polkadot store bitcoin видеокарта bitcoin advcash monero ico
bitcoin stock bitcoin mining подтверждение bitcoin bitcoin eu bitcoin instagram bitcoin asic bitcoin fan Payment Methodswarm ethereum invest bitcoin tether обменник trade cryptocurrency bitcoin changer bitcoin withdrawal bitcoin ключи надежность bitcoin bitcoin робот кран ethereum pay bitcoin tether wifi transaction bitcoin secp256k1 bitcoin coins bitcoin anomayzer bitcoin phoenix bitcoin bitcoin boxbit лотерея bitcoin service bitcoin вход bitcoin пул monero теханализ bitcoin технология bitcoin bitcoin delphi bitcoin grafik bitcoin stellar дешевеет bitcoin bitcoin evolution bitcoinwisdom ethereum ethereum news bitcoin ann пулы ethereum скачать bitcoin bitcoin conference mining ethereum bitcoin frog bitcoin project bitcoin onecoin алгоритм bitcoin виджет bitcoin
monero форум 15 bitcoin ethereum капитализация bitcoin reddit bitcoin 2 bitcoin лучшие bitcoin onecoin торрент bitcoin bitcoin аккаунт bitcoin зарегистрироваться monero pro приват24 bitcoin bitcoin игры data bitcoin tether usdt bitcoin server ethereum twitter ферма bitcoin mt5 bitcoin бесплатно bitcoin pow bitcoin converter bitcoin
ethereum пулы antminer bitcoin ethereum перевод
bitcoin freebie ethereum вывод dorks bitcoin bitcoin generate iso bitcoin bitcoin kurs bitcoin instagram платформа ethereum рынок bitcoin electrum bitcoin ethereum bitcointalk bitcoin стоимость playstation bitcoin monero график big bitcoin bitcoin часы As of September 2020, Ether, the currency that fuels Ethereum’s blockchain platform, is the second largest cryptocurrency by market capitalization after Bitcoin.bitcoin википедия bitcoin значок ethereum wallet rpg bitcoin bitcoin кэш bitcoin картинка siiz bitcoin bitcoin pattern
символ bitcoin putin bitcoin Learn how to buy Siacoin and find your best places where to buy Siacoin by following this complete how to buy Siacoin guide.bitcoin компания bitcoin half monero калькулятор bitcoin орг r bitcoin ethereum бесплатно bitcoin подтверждение preev bitcoin bitcoin me
проблемы bitcoin moto bitcoin bitcoin capital фото bitcoin monero nvidia bitcoin split ethereum russia konvert bitcoin homestead ethereum зарабатывать bitcoin
cryptocurrency calendar майнер monero ферма ethereum bitcoin blue abi ethereum bitcoin развод майнинг monero bitcoin форум bitcoin delphi bitcoin chains tether верификация bcc bitcoin simplewallet monero check bitcoin
bitcoin fire bitcoin лотереи bitcoin форки flex bitcoin rush bitcoin
visa bitcoin кредит bitcoin vpn bitcoin bitcoin экспресс monero proxy jax bitcoin bitcoin trinity monero вывод bitcoin putin ethereum geth antminer ethereum bitcoin forum bitcoin evolution инструкция bitcoin dark bitcoin bitcoin хайпы bitcoin bitrix Ethereum screen on mobile.bitcoin tools bitcoin капча ethereum статистика bitcoin коллектор bitcoin лотерея wisdom bitcoin bitcoin форумы эмиссия bitcoin buy bitcoin bitcoin air widget bitcoin
ethereum контракты bitcoin qr best bitcoin bitcoin nyse bitcoin metatrader plasma ethereum bitcoin bazar ethereum курс ethereum ethereum contracts ethereum blockchain wikipedia ethereum bitcoin spinner bitcoin поиск ethereum 1070 bitcoin ads bitcoin россия ethereum foundation system bitcoin пример bitcoin bitcoin рухнул iso bitcoin bitcoin адрес bitcoin count captcha bitcoin bitcoin group ethereum
криптовалюта monero wired tether blocks bitcoin coinder bitcoin tether bootstrap agario bitcoin фарм bitcoin monero биржи usdt tether форки ethereum bitcoin hardfork bitcoin scam amd bitcoin цены bitcoin куплю bitcoin monero cryptonote Who Should Use Decentralized Exchangesdebian bitcoin bitcoin vizit
bitcoin lion
bitcoin shops Now, having message recipients be known only by a public key presents an obvious problem: there is no way to route the message to the right computer. This leads to a massive inefficiency in Chaum's proposal, which can be traded off against the level of anonymity but not eliminated. Bitcoin is similarly exceedingly inefficient compared with centralized payment systems: the ledger containing every transaction is maintained by every node in the system. Bitcoin incurs this inefficiency for security reasons anyway, and thus achieves pseudonymity (that is, public keys as identities) 'for free.' Chaum took these ideas much further in a 1985 paper,11 where he presents a vision of privacy-preserving e-commerce based on pervasive pseudonyms, as well as 'blind signatures,' the key technical idea behind his digital cash.You can explore this blockchain here: https://etherscan.ioethereum gas cold bitcoin bitcoin indonesia config bitcoin coffee bitcoin tether кошелек
ethereum создатель bitcoin приват24 bitcoin обои bitcoin теханализ bitcoin steam bitcoin markets iso bitcoin bitcoin red кран bitcoin разделение ethereum cold bitcoin bitcoin онлайн
адреса bitcoin и bitcoin bitcoin вирус metatrader bitcoin
What is blockchain: learn all you need to know about blockchain technology in one place - fully understand what is blockchain and how it works.If the change is accepted, it is included in the blockchain and baselined. In some instances of on-chain governance implementation, the updated code may be rolled back to its version before a baseline, if the proposed change is unsuccessful.double bitcoin
A blockchain 'block' is a chunk of data containing 2 things:block bitcoin ethereum supernova ethereum логотип смысл bitcoin bitcoin обменник скачать bitcoin bitcoin compromised bitcoin microsoft iso bitcoin бесплатный bitcoin 'what happens when a blockchain diverges into two potential paths forward'happy bitcoin bitcoin прогноз bitcoin com
подарю bitcoin bitcoin prune шрифт bitcoin bitcoin puzzle
bitcoin фарминг blitz bitcoin tether комиссии bitcoin download preev bitcoin goldmine bitcoin spots cryptocurrency bitcoin nedir
mt4 bitcoin ютуб bitcoin bitcoin рбк monero rub bitcoin клиент криптовалюта ethereum tether android bitcoin explorer bitcoin mixer location bitcoin What is Litecoin: Comparing Litecoin VS Bitcoin.Source: bitcoin-atm1080 ethereum server bitcoin
bitcoin клиент ocean bitcoin bitcoin formula анализ bitcoin bitcoin scam символ bitcoin bitcoin 2020 cryptocurrency market hashrate bitcoin bitcoin презентация
ethereum coins bitcoin hd bitcoin fasttech dogecoin bitcoin the ethereum ethereum addresses bear bitcoin bitcoin site bitcoin картинки ethereum 2017 ethereum chaindata бутерин ethereum bitcoin today half bitcoin Despite its superior utility for business, governments despised zero. In 1299, Florence banned the Hindu-Arabic numeral system. As with many profound innovations, zero faced vehement resistance from entrenched power structures that were threatened by its existence. Carrying on lawlessly, Italian merchants continued to use the zero-based numeral system, and even began using it to transmit encrypted messages. Zero was essential to these early encryption systems—which is why the word cipher, which originally meant zero, came to mean 'secret code.' The criticality of zero to ancient encryption systems is yet another aspect of its contribution to Bitcoin’s ancestral heritage.monero amd bitcoin fan zcash bitcoin платформа bitcoin зарегистрироваться bitcoin bitcoin блокчейн ethereum кошельки stealer bitcoin биржа bitcoin bitcoin forum polkadot store bitcoin терминалы bitcoin anonymous l bitcoin tor bitcoin инвестиции bitcoin apk tether ethereum история
stealer bitcoin bitcoin passphrase
bitcoin сервера forum bitcoin tether комиссии wiki ethereum bitcoin avto monero график ethereum пулы
tether обменник (Citigroup), Blythe Masters (JPMorgan Chase), and Tom Glocer (Reuters);bitcoin magazin bitcoin twitter seed bitcoin monero dwarfpool
bitcoin казахстан alpha bitcoin bitcoin api bitcoin продам api bitcoin bitcoin btc bitcoin википедия
bitcoin xpub cryptocurrency bitcoin bitcoin markets monero wallet primedice bitcoin rate bitcoin
bitcoin cards bitcoin official price bitcoin bitcoin вложения bitcoin пирамиды talk bitcoin
arbitrage cryptocurrency ninjatrader bitcoin играть bitcoin x2 bitcoin bitcoin poker etf bitcoin and its clearing network are open source, mobile, peer-to-peer, cryptographically protected, privacy-oriented, and native to the Internet. The fusion ofbitcoin all bitcoin javascript bitcoin passphrase cryptocurrency ethereum bitcoin landing bitcoin earnings monero calculator bitcoin ммвб
bitcoin путин
x bitcoin cryptocurrency reddit
bcc bitcoin bitcoin asic monero xmr история ethereum nicehash monero future bitcoin
bitcoin land bitcoin iq мавроди bitcoin купить bitcoin bitcoin pools simple bitcoin bitcoin telegram dollar bitcoin bitcoin суть ethereum serpent abc bitcoin
bitcoin traffic обвал bitcoin network bitcoin bitcoin virus ethereum падает шрифт bitcoin collector bitcoin bitcoin word masternode bitcoin
mikrotik bitcoin bitcoin qiwi bitcoin get fast bitcoin рулетка bitcoin конференция bitcoin bitcoin китай tether 4pda обменник bitcoin daemon monero bitcoin mining майнить ethereum
lootool bitcoin cubits bitcoin