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 разделился автомат bitcoin
goldsday bitcoin
bitcoin adress bitcoin аналоги
бот bitcoin bitcoin casino bitcoin space bitcoin poker bux bitcoin
автоматический bitcoin cronox bitcoin bitcoin venezuela
bitcoin падает bitcoin cny bitcoin haqida bitcoin redex вход bitcoin
bitcoin значок ethereum клиент stealer bitcoin bitcoin attack bitcoin карты bitcoin network pinktussy bitcoin ethereum torrent ethereum addresses bitcoin адреса ethereum classic kupit bitcoin currency bitcoin зарабатывать bitcoin kong bitcoin bitcoin preev mikrotik bitcoin mmm bitcoin bitcoin зарегистрироваться wisdom bitcoin bitcoin lurkmore buy tether bitcoin live casinos bitcoin бизнес bitcoin форекс bitcoin pay bitcoin bitcoin окупаемость nicehash monero monero nvidia bitcoin зарабатывать ethereum обвал Ethereum was announced at the North American Bitcoin Conference in Miami, in January 2014. During the same time as the conference, a group of people rented a house in Miami: Gavin Wood, Charles Hoskinson, and Anthony Di Iorio from Toronto who financed the project. Di Iorio invited friend Joseph Lubin, who invited reporter Morgen Peck, to bear witness. Six months later the founders met again in a house in Zug, Switzerland, where Buterin told the founders that the project would proceed as a non-profit. Hoskinson left the project at that time.bitcoin payza хешрейт ethereum deep bitcoin
testnet ethereum продажа bitcoin 600 bitcoin segwit bitcoin 1Backgroundbitcoin puzzle bitcoin alien
bitcoin wm bitcoin yandex tether комиссии bitcoin bitrix бутерин ethereum xmr monero ethereum валюта monero pools технология bitcoin ethereum homestead avto bitcoin bitcoin exchange vps bitcoin bitcoin генераторы bitcoin 999 bitcoin usb ninjatrader bitcoin bitcoin nvidia ethereum заработок To understand both with real-world comparisons, below are some analogies.avatrade bitcoin отзывы ethereum
bitcoin 4000 bitcoin windows 2x bitcoin bitcoin click bitcoin автоматически bitcoin crypto wordpress bitcoin bitcoin tor bitcoin pdf bitcoin code bitcoin moneybox
bitcoin займ bitcoin loan bitcoin apple bitcoin crane For example, if you bought $1000 worth of ETH back in March 2017 and held it long term up until March 2018, you would have $25,000 worth of Ethereum right now. However, if you had sold your Ethereum in December 2017, you would have locked in about $45,000. You could then use some of that money to reinvest into Ether to hold it for another set of profits.проекта ethereum The first miner to solve these equations, and in the process verify transactions on the ledger, gets a reward, which is known as a 'block reward.' This reward is paid out in virtual coins, and is an example of how bitcoin transactions are verified. This process is referred to as 'proof of work.'prune bitcoin Walmart was facing an issue where people were returning goods citing quality issues. Now, in an organization of Walmart’s size and scope, it was quite a task to determine where bad products originated from within their supply chain. Their supply chain involved the following steps: People who take reasonable precautions are safe from having their personal bitcoin caches stolen by hackers.loans bitcoin bitcoin euro usb bitcoin Having a requirement for minimizing trust is a fundamental property that enables many of the other principles covered in this post. These principles can be understood as coming from and working towards a low-trust aim. We’ll never be able to achieve 100% trustlessness as no one has the resources to audit all of the software and hardware they use to interact with the network. However, we can come reasonably close so that we are confident that transparent, incentive-aligned groups of participants are not colluding to the detriment of the rest of the ecosystem.bitcoin suisse java bitcoin blockchain bitcoin bank bitcoin ethereum перспективы bitcoin торговля monero difficulty bitcoin exchanges bitcoin book bitcoin dice bitcoin account bitcoin traffic кошельки ethereum bitcoin nonce bitcoin motherboard cold bitcoin datadir bitcoin vector bitcoin cryptocurrency wallets bitcoin forecast bitcoin check kurs bitcoin bitcoin matrix bitcoin конференция • $3,000 is allocated to an altcoin portfolio consisting of 4-8 currencies. For currencies that have risen a lot lately, the budget is investedethereum продать сложность ethereum ethereum geth bitcoin перевод майнинг monero новости ethereum ethereum online bitcoin бесплатно ethereum контракты escrow bitcoin обновление ethereum
лотереи bitcoin платформы ethereum 60 bitcoin bitcoin заработок abc bitcoin bitcoin рост sberbank bitcoin ethereum news forum bitcoin bitcoin 2017 падение ethereum easy bitcoin bitcoin markets ethereum клиент bitcoin download coin bitcoin new bitcoin виталик ethereum прогнозы bitcoin ethereum форк tether download ферма ethereum mt4 bitcoin parity ethereum value bitcoin bitcoin foto bitcoin лучшие half bitcoin bitcoin click bitcoin nodes monero miner epay bitcoin bitcoin ads mooning bitcoin
bitcoin tools bitcoin курс
е bitcoin ethereum рубль bitcoin scan
bitcoin ruble decred cryptocurrency
bitcoin лотереи tp tether bitcoin generation bitcoin обменники
bitcoin рейтинг куплю bitcoin mikrotik bitcoin биржи monero отдам bitcoin Some legal and accounting firms also accept payment for their services in cryptocurrency.claim bitcoin Because bitcoin transactions are irreversible and there are many faucets, they have become targets for hackers interested in stealing bitcoins. Advertisements are the main income source of bitcoin faucets. Faucets try to get traffic from users by offering free bitcoin as an incentive. Some ad networks also pay directly in bitcoin. This means that faucets often have a low profit margin. Some faucets also make money by mining altcoin in the background, using the user's CPU.отзыв bitcoin polkadot cadaver fox bitcoin bitcoin сбор кошелек ethereum forecast bitcoin bitcoin local bitcoin депозит работа bitcoin bitcoin рбк bitcoin hype bitcoin баланс nasdaq bitcoin bitcoin вложить cryptocurrency tech wild bitcoin bistler bitcoin bitcoin автомат monero minergate ethereum валюта
форк bitcoin ethereum пулы bitcoin golden сборщик bitcoin lurk bitcoin bitcoin word bitcoin advcash bitcoin nyse bitcoin daemon ethereum график instaforex bitcoin bitcoin half konverter bitcoin ethereum coins
ethereum прогнозы bitcoin logo ethereum пул bitcoin rt bitcoin 2017 ethereum mining
monero gpu bitcoin reserve linux bitcoin bitcoin список book bitcoin An organization or an individual person can obtain the power to distort the block chain if it possesses 50% more of the total BTC network’s mining power. This concept is recognized as '51% attack'.wallpaper bitcoin
cubits bitcoin bitcoin bounty bitcoin space ethereum course
bitcoin cz
bitcoin monero bitcoin clicks bitcoin bounty coinder bitcoin bitcoin зарегистрироваться bitcoin 999 bitcoin token bitcoin отслеживание
bitcoin motherboard биржи bitcoin bitcoin putin free bitcoin заработать ethereum bitcoin кошелек скачать bitcoin ethereum news half bitcoin bitcoin grafik
bitcoin исходники bitcoin blockstream monaco cryptocurrency ethereum транзакции box bitcoin кошелька ethereum zcash bitcoin avto bitcoin bitcoin shop bitcoin оплатить bitcoin лохотрон сложность monero
bitcoin завести wikipedia cryptocurrency
bitcoin sportsbook avalon bitcoin mac bitcoin bitcoin land розыгрыш bitcoin important — advantages of blockchain technology.999 bitcoin кошель bitcoin ethereum видеокарты bitcoin вирус community bitcoin
bitcoin mt4 tether майнить super bitcoin up bitcoin script bitcoin bitcoin check график bitcoin bcc bitcoin приложение tether monero cpu local ethereum заработать monero bitcoin автоматом обвал bitcoin monero pro erc20 ethereum wifi tether lavkalavka bitcoin block ethereum bitcoin multisig инструкция bitcoin konvert bitcoin antminer bitcoin
etf bitcoin технология bitcoin simple bitcoin dance bitcoin значок bitcoin трейдинг bitcoin бесплатный bitcoin ethereum проекты bitcoin mt4 magic bitcoin
ethereum кошелька topfan bitcoin 27. Differentiate between Proof of Work vs Proof of Stake.nicehash bitcoin
tether download mixer bitcoin bitcoin valet bitcoin info rx580 monero bitcoin государство wikipedia cryptocurrency ethereum форум платформы ethereum tether io decred cryptocurrency bitcoin мошенничество bitcoin crash фермы bitcoin сайте bitcoin рынок bitcoin сложность bitcoin reindex bitcoin bitcoin пул фермы bitcoin bitcoin nodes