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.
nova bitcoin
bitcoin xpub
pow bitcoin bitcoin information make bitcoin bitcoin кран bitcoin apk кран bitcoin polkadot stingray bitcoin сложность обвал ethereum спекуляция bitcoin metropolis ethereum flypool monero ubuntu bitcoin bitcoin atm ethereum токены love bitcoin That is correct.bitcoin two space bitcoin bitcoin rotators
bitcoin help проверка bitcoin bitcoin purse
hd7850 monero
key bitcoin
bitcoin pool ethereum проекты cardano cryptocurrency usa bitcoin кошель bitcoin bitcoin poker символ bitcoin bitcoin mixer exchanges bitcoin bitcoin motherboard автомат bitcoin bitcoin терминал bitcoin сети monero address
ethereum markets bitcoin segwit2x bitcoin зарегистрироваться nvidia bitcoin биржа bitcoin
бесплатный bitcoin кран monero bitcoin аккаунт bitcoin динамика tether clockworkmod accepts bitcoin bitcoin eth bitcoin сборщик bitcoin anonymous At the moment, the transaction from Alice to Bob is still not confirmed by the network, and Bob can change the witness signature, therefore changing this transaction ID from 12345 to 67890.pplns monero 2016 bitcoin clicker bitcoin 999 bitcoin ethereum raiden invest bitcoin bitcoin mixer
стоимость ethereum ethereum info биткоин bitcoin bitcoin china bitcoin rt bitcoin convert bitcoin перспективы
ethereum vk ico ethereum goldmine bitcoin bitcoin 50 bitcoin click rpc bitcoin cryptocurrency top bitcoin приложение freeman bitcoin форум bitcoin проверка bitcoin bitcoin падение This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages)Gas amountethereum токен
maps bitcoin bitcoin word
bitcoin удвоитель swarm ethereum monero курс bitcoin автор bitcoin трейдинг bitcoin knots trust bitcoin deep bitcoin create bitcoin bitcoin habrahabr topfan bitcoin bitcoin получить
bitcoin cz китай bitcoin
l bitcoin
bitcoin расшифровка p2pool bitcoin bitcoin qazanmaq bitcoin synchronization bitcoin gambling bitcoin пулы talk bitcoin testnet ethereum
bitcoin nyse ethereum пулы bitcoin pump simplewallet monero ethereum metropolis видеокарта bitcoin ethereum install bitcoin casino bitcoin knots кошелек tether ethereum эфириум market bitcoin ethereum получить bitcoin easy monero fr bitcoin новости bitcoin help
claim bitcoin cranes bitcoin airbit bitcoin bitcoin alliance tether bootstrap monero price bitcoin bloomberg бесплатный bitcoin
login bitcoin token ethereum Through this mechanism, miners are maximally incentivized to produce honest, valid work and to work within the consensus of the chain at all times; it is either be paid or receive nothing. It is also why the higher the cost to perform the work, the more secure the network becomes. The more energy required to write or rewrite bitcoin’s transaction history, the lower the probability that any single miner could (or would) undermine the network. The incentive to cooperate increases as it becomes more costly to produce work which would otherwise be considered invalid by the rest of the network. As network security increases, bitcoin becomes more valuable. As the value of bitcoin rises and as the costs to solve blocks increases, the incentive to produce valid work increases (more revenue but more cost) and the penalty for invalid work becomes more punitive (no revenue and more cost). crococoin bitcoin
webmoney bitcoin credit bitcoin bitcoin приложение bitcoin logo обменник monero разработчик bitcoin
ethereum shares расшифровка bitcoin дешевеет bitcoin ads bitcoin ethereum вывод monero форк
Coins and tokens are both cryptocurrencies. The difference is: a coin belongs to its blockchain, whereas a token is built on an existing blockchain. So, there can be thousands of tokens built onto a blockchain, whereas there can only be one coin.ethereum обмен coffee bitcoin bitcoin coin вывод monero bitcoin книга ethereum game cryptocurrency wallet bitcoin poloniex etf bitcoin bitcoin лохотрон bitcoin work
ethereum transactions youtube bitcoin ethereum coins film bitcoin pay bitcoin bitcoin миксеры abi ethereum Cold storage resolves this issue by signing the transaction with the private keys in an offline environment. Any transaction initiated online is temporarily transferred to an offline wallet kept on a device such as a USB, CD, hard drive, paper, or offline computer, where it is then digitally signed before it is transmitted to the online network. Because the private key does not come into contact with a server connected online during the signing process, even if an online hacker comes across the transaction, s/he would not be able to access the private key used for it. In exchange for this added security, the process of transferring to and from a cold storage device is somewhat more burdensome than the process for a hot wallet.asics bitcoin bitcoin cz ethereum перспективы bitcoin flapper
tether usd bitcoin click bitcoin earnings bitcoin greenaddress компьютер bitcoin In a more technical sense, cryptocurrency mining is a transactional process that involves the use of computers and cryptographic processes to solve complex functions and record data to a blockchain. In fact, there are entire networks of devices that are involved in cryptomining and that keep shared records via those blockchains.bitcoin 1000 cranes bitcoin bitcoin satoshi ethereum стоимость ropsten ethereum видео bitcoin bitcoin swiss bitcoin future bitcoin заработок cryptocurrency mining bitcoin автосборщик эмиссия bitcoin unconfirmed bitcoin testnet ethereum converter bitcoin ava bitcoin математика bitcoin io tether котировки bitcoin
продать monero ethereum com tether clockworkmod ethereum биткоин monero сложность использование bitcoin bitcoin nodes bitcoin loan bitcoin ваучер 1080 ethereum bitcoin зарегистрироваться bitcoin token
bitcoin email bitcoin dump Easy to set upmonero coin
bitcoin converter приложение tether bitcoin ставки
bubble bitcoin bitcoin office bitcoin sha256 tether программа bitcoin динамика in bitcoin stock bitcoin bitcoin frog сколько bitcoin bitcoin прогноз pro100business bitcoin bitcoin reindex bitcoin отслеживание асик ethereum bitcoin скачать bitcoin cny bitcointalk bitcoin
bitcoin video bitcoin explorer ecopayz bitcoin ethereum course bitcoin arbitrage flypool monero 16 bitcoin bitcoin checker half bitcoin bitcointalk ethereum
bitcoin путин bitcoin окупаемость At the top of the cypherpunks, the to-do list was digital cash. DigiCash and Cybercash were both attempts to create a digital money system. They both had some of the six things needed to be cryptocurrencies but neither had all of them. By the end of thebitcoin motherboard One of the key features of Ethereum is that it allows for both permissioned and permissionless transactions.wifi tether разработчик bitcoin lamborghini bitcoin bitcoin super bitcoin collector
ethereum supernova loan bitcoin Zero: An Ideological Juggernautblocks bitcoin ethereum os win bitcoin monero price equihash bitcoin ethereum хешрейт coingecko ethereum bitcoin скачать monero miner 4pda tether курс ethereum bitcoin ne обвал ethereum python bitcoin bitcoin earn bitcoin продам bitcoin earn roboforex bitcoin кошель bitcoin world bitcoin ethereum blockchain bitcoin earning форекс bitcoin monero калькулятор sberbank bitcoin shot bitcoin lootool bitcoin bitcoin asics mmm bitcoin nicehash monero moon bitcoin bitcoin халява bitcoin cny bitcoin проблемы блок bitcoin краны monero трейдинг bitcoin кран bitcoin bitcoin терминал ethereum coin monero nicehash значок bitcoin fpga bitcoin sun bitcoin криптовалют ethereum bitcoin сервера депозит bitcoin ethereum перспективы почему bitcoin монета ethereum
bitcoin стоимость habrahabr bitcoin
avto bitcoin bitcoin установка кошелька ethereum ethereum complexity инструкция bitcoin neteller bitcoin bitcoin word форекс bitcoin The 'Greedy Heaviest Observed Subtree' (GHOST) protocol is an innovation first introduced by Yonatan Sompolinsky and Aviv Zohar in December 2013. The motivation behind GHOST is that blockchains with fast confirmation times currently suffer from reduced security due to a high stale rate - because blocks take a certain time to propagate through the network, if miner A mines a block and then miner B happens to mine another block before miner A's block propagates to B, miner B's block will end up wasted and will not contribute to network security. Furthermore, there is a centralization issue: if miner A is a mining pool with 30% hashpower and B has 10% hashpower, A will have a risk of producing a stale block 70% of the time (since the other 30% of the time A produced the last block and so will get mining data immediately) whereas B will have a risk of producing a stale block 90% of the time. Thus, if the block interval is short enough for the stale rate to be high, A will be substantially more efficient simply by virtue of its size. With these two effects combined, blockchains which produce blocks quickly are very likely to lead to one mining pool having a large enough percentage of the network hashpower to have de facto control over the mining process.bitcoin greenaddress bitcoin background майнеры ethereum дешевеет bitcoin dag ethereum bitcoin динамика добыча bitcoin bitcoin кошельки bitcoin мошенники bitcoin buying bitcoin проблемы
bitcoin miner bitcoin greenaddress skrill bitcoin генераторы bitcoin брокеры bitcoin abi ethereum half bitcoin bitcoin логотип форк bitcoin bitcoin окупаемость bitcoin exe cryptocurrency calendar tether верификация bitcoin приложение rx580 monero bitfenix bitcoin bitcoin игры bitcoin автоматически bitcoin capitalization cubits bitcoin bitcoin википедия bitcoin обменник airbitclub bitcoin bitcoin прогноз bitcoin транзакции bitcoin бесплатно ethereum форк lealana bitcoin
bitcoin loans
bitcoin bear bitcoin роботы ethereum регистрация bitcoin окупаемость monero 1070 добыча bitcoin get bitcoin bitcoin компьютер стоимость bitcoin stellar cryptocurrency status bitcoin bitcoin принцип конвектор bitcoin 1060 monero ann ethereum ethereum decred 2016 bitcoin konvert bitcoin card bitcoin jax bitcoin sec bitcoin
bitcoin обменники зарабатывать bitcoin bitcoin команды arbitrage cryptocurrency free monero bitcoin loan bitcoin matrix vector bitcoin рост bitcoin wirex bitcoin bitcoin команды reddit cryptocurrency депозит bitcoin bitcoin ixbt bitcoin talk clame bitcoin bitcoin metal
boom bitcoin cronox bitcoin monero пул flash bitcoin word bitcoin cryptocurrency charts wiki bitcoin настройка bitcoin
bitcoin transaction
форум bitcoin bitcoin xl bitcoin торги monero pro bitcoin ключи ethereum бесплатно настройка monero bitcoin king ethereum регистрация coinmarketcap bitcoin bitcoin значок bitcoin магазины freeman bitcoin bitcoin purchase trezor bitcoin habrahabr bitcoin ninjatrader bitcoin шифрование bitcoin bitcoin skrill ethereum claymore ethereum пул
antminer ethereum
tether 4pda tokens ethereum buy tether работа bitcoin
bitcoin обмен bitcoin antminer
bitcoin игры ethereum casper bitcoin sweeper bitcoin проверить кошелька bitcoin solo bitcoin best bitcoin The proof-of-work chain is how all the synchronisation, distributed database and global view problems you’ve asked about are solved.bitcoin crush bitcoin xyz ethereum хешрейт easy bitcoin bitcoin work ethereum casino
600 bitcoin
bitcoin usb tp tether bitcoin compare bitcoin easy bitcoin exchange buy ethereum bitcoin шахты tcc bitcoin bitcoin play ethereum classic bitcoin conveyor bitcoin moneybox bitcoin store bitcoin token ethereum claymore криптовалюту bitcoin сбербанк bitcoin bitcoin софт
mercado bitcoin обмен tether wild bitcoin bitcoin хабрахабр in bitcoin polkadot su bitcoin loto
bitcoin рейтинг ninjatrader bitcoin
ethereum транзакции рулетка bitcoin bitcoin 20 twitter bitcoin weather bitcoin 1024 bitcoin
ethereum фото bitcoin atm half bitcoin machines bitcoin bitcoin exchanges купить ethereum ethereum график bitcoin приват24
bitcoin luxury blender bitcoin
collector bitcoin finney ethereum bitcoin api bitcoin sec future bitcoin service bitcoin вывод bitcoin обновление ethereum raiden ethereum bitcoin видеокарты blake bitcoin bitcoin инструкция bitcoin минфин wikileaks bitcoin ethereum заработок copay bitcoin generate bitcoin bitcoin безопасность top bitcoin ru bitcoin
bitcoin conveyor комиссия bitcoin claymore monero supernova ethereum bitcoin s transactions bitcoin
china bitcoin
сети bitcoin компьютер bitcoin
monero proxy
контракты ethereum bitcoin сигналы bubble bitcoin bitcoin x2 gift bitcoin bitcoin plus win bitcoin takara bitcoin ethereum хешрейт продам bitcoin bitcoin xt download bitcoin freeman bitcoin world bitcoin token bitcoin genesis bitcoin платформу ethereum xmr monero использование bitcoin loan bitcoin
майнер ethereum bitcoin traffic
logo ethereum ico bitcoin bitcoin ocean Is resistant to fork attacks from large ASIC miners, with plenty of hashrate or fork-resistant mechanisms.putin bitcoin geth ethereum nxt cryptocurrency
бесплатный bitcoin weekend bitcoin tether верификация
bitcoin euro bitcoin send monero алгоритм bitcoin транзакция segwit2x bitcoin майн bitcoin In September 2014 TeraExchange, LLC, received approval from the U.S.Commodity Futures Trading Commission 'CFTC' to begin listing an over-the-counter swap product based on the price of a bitcoin. The CFTC swap product approval marks the first time a U.S. regulatory agency approved a bitcoin financial product.ico bitcoin bitcoin пирамиды игра ethereum
форк bitcoin bitcoin legal ethereum telegram hd bitcoin анонимность bitcoin
bitcoin pizza ethereum wallet bitcoin faucets monero стоимость coindesk bitcoin bitcoin brokers транзакции ethereum monero blockchain обменник tether форк bitcoin
bitcoin hunter moneybox bitcoin форк bitcoin bitcoin валюта nicehash monero monero blockchain bitcoin funding dark bitcoin суть bitcoin падение bitcoin bitcoin loans ethereum сайт bitcoin php