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.
bitcoin сети Image for post
ethereum chaindata
bitcoin today bitcoin grafik fork bitcoin flypool monero abc bitcoin
платформы ethereum bitcoin department ethereum dag
monero bitcointalk bitcoin click bitcoin cudaminer weekend bitcoin bitcoin vps algorithm ethereum Try to convince the network that his transaction to himself was the one that came first.Not only that, the quality of investment will actually be greater as both consumption and investment benefit from undistorted price signals and with the opportunity cost of money being more clearly priced by a free market. When all spending decisions are evaluated against an expectation of potentially greater purchasing power in the future (rather than less), investments will be steered toward the most productive activities and day-to-day consumption will be filtered with greater scrutiny.bitcoin online bitcoin laundering Also, a number of large and small retailers accept the cryptocurrency as a form of payment, although reports suggest that demand for this function is not high.distinct history on the public ledger.However, where you start to tread into the territory of illegal activities is when you use illicit means to mine cryptocurrencies. For example, some cybercriminals use Javascript in browsers or install malware on unsuspecting users’ devices to 'hijack' their devices’ processing power. This type of cyber attack is known as cryptojacking. We’re going to publish a separate article on that topic later this month, so stay tuned.fake bitcoin бесплатно ethereum депозит bitcoin doubler bitcoin monero обменять monero обменник monero client bitcoin explorer monero xeon бот bitcoin magic bitcoin брокеры bitcoin abc bitcoin исходники bitcoin cryptocurrency arbitrage day bitcoin сервер bitcoin bitcoin maps Simple, they’re applications running on the blockchain. Decentralized blockchain apps are harder to tamper with than traditional apps. It sounds complicated, yet it’s not.amazon bitcoin bitcoin register mastercard bitcoin bitcoin cran monero github bitcoin часы кошельки ethereum faucet cryptocurrency facebook bitcoin ethereum github up bitcoin wallets cryptocurrency bitcoin создать bitcoin monkey bitcoin satoshi ethereum swarm значок bitcoin fpga ethereum the ethereum новости bitcoin bitcoin регистрации ebay bitcoin faucets bitcoin monero пул bitcoin биткоин bitcoin block monero cryptonote доходность ethereum ethereum nicehash bitcoin nonce golang bitcoin bitcoin block
bitcoin plus bitcoin forex pull bitcoin space bitcoin
bitcoin тинькофф monero price 60 bitcoin bitcoin server bitcoin монеты bitcoin tor ava bitcoin bitcoin instaforex delphi bitcoin charts bitcoin заработка bitcoin bitcoin scanner bitcoin mmgp oil bitcoin bitcoin changer bitcoin preev ethereum btc decred ethereum short bitcoin
keepkey bitcoin сети ethereum биржа ethereum cran bitcoin tether транскрипция wallets cryptocurrency bitcoin signals wmx bitcoin и bitcoin
bitcoin котировка
криптовалюту monero bitcoin bitcointalk monero криптовалюта bitcoin ocean bitcoin рубль tether chvrches
ethereum виталий
lamborghini bitcoin carding bitcoin bitcoin generation arbitrage bitcoin split bitcoin bitcoin monkey
monero windows обменники ethereum bitcoin yandex nicehash monero bitcoin блог цена ethereum bitcoin ether
bitcoin matrix bitcoin paper bitcoin change plus500 bitcoin bitcoin bear bitcoin автоматически ethereum ротаторы dog bitcoin blitz bitcoin mikrotik bitcoin
количество bitcoin bitcoin king bitcoin ebay тинькофф bitcoin
сайте bitcoin bitcoin основы bitcoin convert ethereum charts bitcoin poloniex bitcoin капитализация hack bitcoin monero 1070 майнеры monero bitcoin withdrawal bitcoin flip neo cryptocurrency пулы monero ethereum addresses bitcoin проверить tinkoff bitcoin Encrypted data –can be read by participants with a decryption key. The key provides access to the data on the blockchain and can prove who added the data and when it was added.sberbank bitcoin перевод ethereum bitcoin hardfork bitcoin mmgp ethereum node
q bitcoin flash bitcoin coins bitcoin platinum bitcoin telegram bitcoin spend bitcoin bitcoin ann статистика ethereum xpub bitcoin ethereum форум ethereum покупка tx bitcoin ethereum bitcoin service bitcoin bitcoin count php bitcoin
gek monero birds bitcoin
advcash bitcoin bitcoin dice ethereum swarm bitcoin халява bitcoin like wisdom bitcoin bitcoin virus
bitcoin vk blocks bitcoin all bitcoin bitcoin игры bitcoin trojan cryptocurrency это bitcoin alliance прогноз ethereum bitcoin монета bitcoin настройка cryptocurrency reddit ethereum видеокарты bitcoin pools iso bitcoin coinmarketcap bitcoin алгоритмы ethereum иконка bitcoin bitcoin matrix bitcoin bitcointalk bitcoin шахта
bitcoin play
maining bitcoin bitcoin paw 6See alsocoin bitcoin яндекс bitcoin пример bitcoin bitcoin com bitcoin автосерфинг bitcoin терминал проблемы bitcoin bitcoin xl bitcoin utopia bitcoin captcha bitcoin get расчет bitcoin bitcoin average bitcoin sign 999 bitcoin bitcoin exchanges wallet cryptocurrency bonus bitcoin bloomberg bitcoin ico bitcoin microsoft bitcoin скачать ethereum search bitcoin bitcoin биржи bitcoin компания bye bitcoin microsoft bitcoin matteo monero cgminer ethereum
bitcoin webmoney secp256k1 ethereum node bitcoin
red bitcoin ethereum contracts ethereum покупка mooning bitcoin bitfenix bitcoin flappy bitcoin конец bitcoin bitcoin форекс monero address
bitcoin markets bitcoin prominer продажа bitcoin stellar cryptocurrency дешевеет bitcoin фото bitcoin currency bitcoin bitcoin demo bitcoin 4 бесплатный bitcoin ethereum platform
bitcoin kaufen bitcoin доллар bitcoin vizit monero биржи best cryptocurrency bitcoin майнить
us bitcoin bitcoin оборудование эмиссия ethereum payza bitcoin tether майнинг LTC Pricefpga ethereum
bitcoin investment Trading is really pretty simple! If you have any questions about buying litecoin, let us know. Our support staff is online all day, every day, ready to help.bitcoin pizza
Around 72 million ETH were created for the crowdsale in July/Aug 2014. This is sometimes called a ‘pre-mine’. It was decided that post-crowdsale, future ETH generation would be capped at 25% of that per year (ie no more than 18m ETH could be mined per year, in addition to the one-off -72m ETH generated for the crowdsale).cryptocurrency rates bitcoin reindex bitcoin cryptocurrency bitcoin индекс tether usd bitcoin платформа by bitcoin ethereum виталий reddit ethereum bitcoin основы
vpn bitcoin анализ bitcoin добыча bitcoin программа ethereum
bitcoin информация статистика ethereum bitcoin skrill monero hardware bitcoin brokers bitcoin окупаемость 0 bitcoin взлом bitcoin bitcoin knots lootool bitcoin терминалы bitcoin пример bitcoin monero кран ethereum casino value bitcoin bitcoin bazar bitcoin oil cryptocurrency law получить bitcoin bitcoin broker lazy bitcoin cryptocurrency arbitrage bitcoin автоматически bitcoin шахты bitcoin cli
bitcoin 123 ethereum 1080 python bitcoin ethereum course биржа bitcoin tor bitcoin The Mt.Gox liquidity problems. When the biggest exchange Mt.Gox suspended bitcoin and fiat withdrawals without a possibility of refunding due to backend evaluation and repairs, bitcoin price declined sharply. The bitcoin value cratered following the mass media announcements. What is more, such event made a knock-on effect on the whole bitcoin industry including other exchanges, thus influenced the bitcoin price in a long-term.all cryptocurrency разработчик ethereum шрифт bitcoin bitcoin анимация bitcoin mine 1080 ethereum bitcoin local bitcoin stellar bitcoin casascius
bitcoin tm rx580 monero ethereum decred торрент bitcoin hash bitcoin ru bitcoin
cryptocurrency bitcoin