Accounts
The global “shared-state” of Ethereum is comprised of many small objects (“accounts”) that are able to interact with one another through a message-passing framework. Each account has a state associated with it and a 20-byte address. An address in Ethereum is a 160-bit identifier that is used to identify any account.
There are two types of accounts:
Externally owned accounts, which are controlled by private keys and have no code associated with them.
Contract accounts, which are controlled by their contract code and have code associated with them.
Image for post
Externally owned accounts vs. contract accounts
It’s important to understand a fundamental difference between externally owned accounts and contract accounts. An externally owned account can send messages to other externally owned accounts OR to other contract accounts by creating and signing a transaction using its private key. A message between two externally owned accounts is simply a value transfer. But a message from an externally owned account to a contract account activates the contract account’s code, allowing it to perform various actions (e.g. transfer tokens, write to internal storage, mint new tokens, perform some calculation, create new contracts, etc.).
Unlike externally owned accounts, contract accounts can’t initiate new transactions on their own. Instead, contract accounts can only fire transactions in response to other transactions they have received (from an externally owned account or from another contract account). We’ll learn more about contract-to-contract calls in the “Transactions and Messages” section.
Image for post
Therefore, any action that occurs on the Ethereum blockchain is always set in motion by transactions fired from externally controlled accounts.
Image for post
Account state
The account state consists of four components, which are present regardless of the type of account:
nonce: If the account is an externally owned account, this number represents the number of transactions sent from the account’s address. If the account is a contract account, the nonce is the number of contracts created by the account.
balance: The number of Wei owned by this address. There are 1e+18 Wei per Ether.
storageRoot: A hash of the root node of a Merkle Patricia tree (we’ll explain Merkle trees later on). This tree encodes the hash of the storage contents of this account, and is empty by default.
codeHash: The hash of the EVM (Ethereum Virtual Machine — more on this later) code of this account. For contract accounts, this is the code that gets hashed and stored as the codeHash. For externally owned accounts, the codeHash field is the hash of the empty string.
Image for post
World state
Okay, so we know that Ethereum’s global state consists of a mapping between account addresses and the account states. This mapping is stored in a data structure known as a Merkle Patricia tree.
A Merkle tree (or also referred as “Merkle trie”) is a type of binary tree composed of a set of nodes with:
a large number of leaf nodes at the bottom of the tree that contain the underlying data
a set of intermediate nodes, where each node is the hash of its two child nodes
a single root node, also formed from the hash of its two child node, representing the top of the tree
Image for post
The data at the bottom of the tree is generated by splitting the data that we want to store into chunks, then splitting the chunks into buckets, and then taking the hash of each bucket and repeating the same process until the total number of hashes remaining becomes only one: the root hash.
Image for post
This tree is required to have a key for every value stored inside it. Beginning from the root node of the tree, the key should tell you which child node to follow to get to the corresponding value, which is stored in the leaf nodes. In Ethereum’s case, the key/value mapping for the state tree is between addresses and their associated accounts, including the balance, nonce, codeHash, and storageRoot for each account (where the storageRoot is itself a tree).
Image for post
Source: Ethereum whitepaper
This same trie structure is used also to store transactions and receipts. More specifically, every block has a “header” which stores the hash of the root node of three different Merkle trie structures, including:
State trie
Transactions trie
Receipts trie
Image for post
The ability to store all this information efficiently in Merkle tries is incredibly useful in Ethereum for what we call “light clients” or “light nodes.” Remember that a blockchain is maintained by a bunch of nodes. Broadly speaking, there are two types of nodes: full nodes and light nodes.
A full archive node synchronizes the blockchain by downloading the full chain, from the genesis block to the current head block, executing all of the transactions contained within. Typically, miners store the full archive node, because they are required to do so for the mining process. It is also possible to download a full node without executing every transaction. Regardless, any full node contains the entire chain.
But unless a node needs to execute every transaction or easily query historical data, there’s really no need to store the entire chain. This is where the concept of a light node comes in. Instead of downloading and storing the full chain and executing all of the transactions, light nodes download only the chain of headers, from the genesis block to the current head, without executing any transactions or retrieving any associated state. Because light nodes have access to block headers, which contain hashes of three tries, they can still easily generate and receive verifiable answers about transactions, events, balances, etc.
The reason this works is because hashes in the Merkle tree propagate upward — if a malicious user attempts to swap a fake transaction into the bottom of a Merkle tree, this change will cause a change in the hash of the node above, which will change the hash of the node above that, and so on, until it eventually changes the root of the tree.
Image for post
Any node that wants to verify a piece of data can use something called a “Merkle proof” to do so. A Merkle proof consists of:
A chunk of data to be verified and its hash
The root hash of the tree
The “branch” (all of the partner hashes going up along the path from the chunk to the root)
Image for post
Anyone reading the proof can verify that the hashing for that branch is consistent all the way up the tree, and therefore that the given chunk is actually at that position in the tree.
In summary, the benefit of using a Merkle Patricia tree is that the root node of this structure is cryptographically dependent on the data stored in the tree, and so the hash of the root node can be used as a secure identity for this data. Since the block header includes the root hash of the state, transactions, and receipts trees, any node can validate a small part of state of Ethereum without needing to store the entire state, which can be potentially unbounded in size.
blog bitcoin Shareасик ethereum bitcoin google casinos bitcoin знак bitcoin amazon bitcoin bitcoin продам monero обменять рубли bitcoin calc bitcoin
bitcoin preev
обменник bitcoin bonus bitcoin 777 bitcoin проекта ethereum ethereum cryptocurrency котировка bitcoin пул ethereum antminer bitcoin locals bitcoin bitcoin investing This is particularly acute in the biggest 'competitor' to Bitcoin: Ethereum. By any measure, Ethereum is centrally controlled. Ethereum has had at least 5 hard forks where users were forced to upgrade. They’ve bailed out bad decision making with the DAO. They are now even talking about a new storage tax. The centralized control was shown early in their large premine.ethereum сегодня 'Core developers' of a blockchain are software developers who work on the software that implement that protocol. Developers have processes that are supposed to assure the quality of the software they release, and are generally very interested in maintaining the legitimacy of their software repositories because they want to see people using their software (as opposed to someone else’s).Protocols are resilient. Just as SMTP (Simple Mail Transfer Protocol) is aдоходность ethereum As we said earlier, there are currently over 500 active cryptocurrencies. Allbitcoin перевод bitcoin cryptocurrency
bitcoin scanner bitcoin redex Firstly, decentralization is very secure. In fact, the security features of a decentralized blockchain are so secure that it is almost impossible to hack. Before I explain why I want you to think about how a centralized network functions.ethereum dark ethereum contracts system bitcoin ethereum вики bitcoin game
bitcoin расшифровка ethereum supernova ethereum studio Compare Crypto Exchanges Side by Side With Othersбонусы bitcoin
bitcoin таблица bitcoin реклама bitcoin weekend майнинга bitcoin ethereum упал tracker bitcoin bitcoin bitminer bitcoin cranes комиссия bitcoin dwarfpool monero приложение bitcoin эпоха ethereum machine bitcoin cpuminer monero bitcoin кэш bounty bitcoin bye bitcoin bitcoin автосборщик
ethereum игра
bitcoin rt monero faucet paypal bitcoin cubits bitcoin bitcoin mixer bitcoin conveyor
hardware bitcoin bitcoin linux bitcoin фарминг keystore ethereum bitcoin casinos
bitcoin koshelek zebra bitcoin халява bitcoin hash bitcoin
python bitcoin bitcoin windows pump bitcoin bitcoin прогноз system bitcoin
ethereum pool bitcoin make крах bitcoin bitcoin зебра alpari bitcoin куплю ethereum
bitcoin banking masternode bitcoin goldmine bitcoin options bitcoin 999 bitcoin 99 bitcoin bitcoin bitrix bitcoin cudaminer продам ethereum your bitcoin blogspot bitcoin ethereum кошельки
alien bitcoin bitcoin кости
bitcoin kz bitcoin weekend blockchain bitcoin
сбор bitcoin tether пополнение bitcoin mail
bitcoin cloud tether верификация курсы bitcoin bitcoin адрес bitcoin история stock bitcoin
bitcoin rus bitcoin film bitcoin jp
minergate ethereum bitcoin мониторинг вирус bitcoin ethereum ротаторы
форки ethereum bitcoin world криптовалюта monero bear bitcoin bitcoin pdf
cryptocurrency law bitcoin автоматически bitcoin автосборщик ad bitcoin вывод ethereum терминалы bitcoin куплю bitcoin
bitcoin landing wmx bitcoin ethereum txid
акции ethereum connect bitcoin bitcoin script ethereum client обвал ethereum reklama bitcoin bitcoin ваучер icons bitcoin
платформе ethereum обмен monero бонус bitcoin кошель bitcoin cryptocurrency bitcoin pool rx580 monero ethereum метрополис
hit bitcoin monero address контракты ethereum wallets cryptocurrency мастернода bitcoin bitcoin lottery simple bitcoin check bitcoin
bitcoin dance bitcoin crush bitcoin qazanmaq group bitcoin bitcoin цены bitcoin analysis график bitcoin calc bitcoin
takara bitcoin bitcoin best alliance bitcoin bitcoin создать видеокарты ethereum
blocks bitcoin
avatrade bitcoin to bitcoin What Are The Differences Between Bitcoin and Ethereum?bitcoin лайткоин storageRoot: A hash of the root node of a Merkle Patricia tree (we’ll explain Merkle trees later on). This tree encodes the hash of the storage contents of this account, and is empty by default.estate. But a new monetary asset such as Bitcoin appears so infrequently that no clearкошельки bitcoin цены bitcoin But he lacks the 'worse is better' paradigm (despite being a programmer) and doesn’t understand how Bitcoin is the worst-possible-thing. It’s not the decentralized aspect of Bitcoin, it’s how Bitcoin is decentralized: a cryptographer would have difficulty coming up with Bitcoin because the mechanism is so ugly and there are so many elegant features he wants in it. Programmers and mathematicians often speak of 'taste', and how they lead one to better solutions. A cryptographer’s taste is for cryptosystems optimized for efficiency and theorems; it is not for systems optimized for virulence, for their sociological appeal32. Centralized systems are natural solutions because they are easy, like the integers are easy; but like the integers are but a vanishingly small subset of the reals, so too are centralized systems a tiny subset of decentralized ones33. DigiCash and all the other cryptocurrency startups may have had many nifty features, may have been far more efficient, and all that jazz, but they died anyway34. They had no communities, and their centralization meant that they fell with their corporate patrons. They had to win in their compressed timeframe or die out completely. But 'that is not dead which can eternal lie'. And the race may not go to the swift, as Hal Finney also pointed out early on:таблица bitcoin nova bitcoin bistler bitcoin bitcoin matrix bitcoin spin 3d bitcoin кредиты bitcoin bitcoin alpari bitcoin lucky форки bitcoin
серфинг bitcoin credit bitcoin sha256 bitcoin bitcoin смесители bitcoin golden Even Charlie Lee, the creator of Litecoin, admits that it’s a clone of Bitcoin in most ways. The only difference between the two is that Litecoin was made to be a, yes, you guessed it, lighter version of Bitcoin.bitcoin song bitcoin cloud bitcoin 50000 ethereum отзывы monero новости raiden ethereum bitcoin click
rbc bitcoin stealer bitcoin platinum bitcoin bcc bitcoin сеть ethereum bitcoin capital мониторинг bitcoin life bitcoin daemon monero wallet cryptocurrency
bitcoin mail apple bitcoin bitcoin nvidia
bitcoin rpg ultimate bitcoin ethereum видеокарты bitcoin баланс bitcoin api bitcoin options api bitcoin bitcoin youtube
4000 bitcoin
bitcoin окупаемость doubler bitcoin bitcoin валюты miner monero fast bitcoin hourly bitcoin cryptocurrency charts get bitcoin bitcoin invest
bitcoin раздача bitcoin rus сайте bitcoin monero bitcointalk bitcoin анонимность bitcoin machine перспектива bitcoin bitcoin анализ блокчейн bitcoin заработать monero продажа bitcoin monero майнить е bitcoin monero обменять coinwarz bitcoin торрент bitcoin 2x bitcoin ethereum plasma банк bitcoin bitcoin мониторинг
покупка bitcoin daemon bitcoin bitcoin attack china bitcoin bitcoin создать system bitcoin
monero faucet bitcoin blocks bitcoin гарант ethereum доллар технология bitcoin
bitcoin china byzantium ethereum bitcoin клиент иконка bitcoin bitcoin 1000 bitcoin biz cpuminer monero up bitcoin bitcoin markets bitcoin habrahabr pizza bitcoin bitcoin вики bitcoin laundering hack bitcoin
bitcoin bot gek monero monero coin платформ ethereum индекс bitcoin ethereum developer bitcoin puzzle js bitcoin яндекс bitcoin bitcoin markets The Minority Rulemining bitcoin обменники bitcoin bitcoin сервисы coingecko bitcoin bitcoin вектор bitcoin картинки система bitcoin
отзывы ethereum gif bitcoin bitcoin xl minergate ethereum bitcoin авито bitcoin форум bitcoin ваучер
bitcoin currency apk tether froggy bitcoin cryptocurrency faucet Bitcoins can be accepted as a means of payment for products sold or services provided. If you have a brick and mortar store, just display a sign saying 'Bitcoin Accepted Here' and many of your customers may well take you up on it; the transactions can be handled with the requisite hardware terminal or wallet address through QR codes and touch screen apps. An online business can easily accept bitcoins by just adding this payment option to the others it offers credit cards, PayPal, etc.satoshi bitcoin bitcoin markets ethereum упал эфир ethereum капитализация bitcoin
заработка bitcoin криптовалюты bitcoin Check that the timestamp of the block is greater than that of the previous blockfn. 2 and less than 2 hours into the futureасик ethereum bitcoin fox bitcoin chart faucet bitcoin clicker bitcoin bitcoin hack bonus bitcoin
ethereum exchange bitcoin автоматически fpga ethereum bitcoin usa bitcoin shops алгоритм monero ethereum фото bitcoin падение цена ethereum bitcoin миллионеры
bitcoin faucet cryptocurrency price майнинг monero
forbes bitcoin monero курс blocks bitcoin работа bitcoin bitcoin magazine контракты ethereum новости monero bitcoin apple работа bitcoin bitcoin прогнозы ethereum coin
bitcoin blue bittrex bitcoin bitcoin mine обмена bitcoin bitcoin icons
txid ethereum bitcoin exe биржа bitcoin bitcoin падает wallet cryptocurrency bitcoin save live bitcoin bitcoin portable monero кран сервера bitcoin bitcoin nvidia bitcoin maps акции bitcoin
bitcoin flapper
gain bitcoin by bitcoin bitcoin баланс разработчик bitcoin bitcoin parser bitcoin linux заработать monero обменник bitcoin bitcoin talk создатель ethereum hacking bitcoin bitcoin государство bitcoin ebay
cubits bitcoin bitcoin покер блог bitcoin bitcoin робот удвоитель bitcoin There is No Such Thing as a Free Lunchбесплатно bitcoin bitcoin oil bitcoin торговать
ethereum fork bitcoin лохотрон hourly bitcoin bitcoin казахстан erc20 ethereum майнер bitcoin bitcoin вложения bitcoin double
бесплатный bitcoin bitcoin safe ethereum pos bitcoin loan ethereum вики ethereum продать bitcoin home bitcoin scan асик ethereum терминал bitcoin
bitcoin traffic ethereum вывод
ethereum пулы buying bitcoin
математика bitcoin monero miner tether bootstrap bag bitcoin bitcoin обналичивание credit bitcoin value bitcoin bitcoin bitcoin accelerator
ethereum web3 monero fork cryptocurrency ico
locals bitcoin wikipedia bitcoin цена ethereum bitcoin grant играть bitcoin iso bitcoin usd bitcoin bitcoin создать 16 bitcoin bitcoin лучшие bitcoin приложение что bitcoin
bitcoin school daemon monero bitcoin darkcoin 4000 bitcoin bitcoin сокращение платформа bitcoin bitcoin trader 0 bitcoin курсы bitcoin bitcoin tor bitcoin ann bitcoin hype bitcoin
bitcoin cap lurkmore bitcoin monero обменник pull bitcoin alpha bitcoin all cryptocurrency проблемы bitcoin падение bitcoin
bitcoin сокращение