Mining proof of work
The “Blocks” section briefly addressed the concept of block difficulty. The algorithm that gives meaning to block difficulty is called Proof of Work (PoW).
Ethereum’s proof-of-work algorithm is called “Ethash” (previously known as Dagger-Hashimoto).
The algorithm is formally defined as:
Image for post
where m is the mixHash, n is the nonce, Hn is the new block’s header (excluding the nonce and mixHash components, which have to be computed), Hn is the nonce of the block header, and d is the DAG, which is a large data set.
In the “Blocks” section, we talked about the various items that exist in a block header. Two of those components were called the mixHash and the nonce. As you may recall:
mixHash is a hash that, when combined with the nonce, proves that this block has carried out enough computation
nonce is a hash that, when combined with the mixHash, proves that this block has carried out enough computation
The PoW function is used to evaluate these two items.
How exactly the mixHash and nonce are calculated using the PoW function is somewhat complex, and something we can delve deeper into in a separate post. But at a high level, it works like this:
A “seed” is calculated for each block. This seed is different for every “epoch,” where each epoch is 30,000 blocks long. For the first epoch, the seed is the hash of a series of 32 bytes of zeros. For every subsequent epoch, it is the hash of the previous seed hash. Using this seed, a node can calculate a pseudo-random “cache.”
This cache is incredibly useful because it enables the concept of “light nodes,” which we discussed previously in this post. The purpose of light nodes is to afford certain nodes the ability to efficiently verify a transaction without the burden of storing the entire blockchain dataset. A light node can verify the validity of a transaction based solely on this cache, because the cache can regenerate the specific block it needs to verify.
Using the cache, a node can generate the DAG “dataset,” where each item in the dataset depends on a small number of pseudo-randomly-selected items from the cache. In order to be a miner, you must generate this full dataset; all full clients and miners store this dataset, and the dataset grows linearly with time.
Miners can then take random slices of the dataset and put them through a mathematical function to hash them together into a “mixHash.” A miner will repeatedly generate a mixHash until the output is below the desired target nonce. When the output meets this requirement, this nonce is considered valid and the block can be added to the chain.
Mining as a security mechanism
Overall, the purpose of the PoW is to prove, in a cryptographically secure way, that a particular amount of computation has been expended to generate some output (i.e. the nonce). This is because there is no better way to find a nonce that is below the required threshold other than to enumerate all the possibilities. The outputs of repeatedly applying the hash function have a uniform distribution, and so we can be assured that, on average, the time needed to find such a nonce depends on the difficulty threshold. The higher the difficulty, the longer it takes to solve for the nonce. In this way, the PoW algorithm gives meaning to the concept of difficulty, which is used to enforce blockchain security.
What do we mean by blockchain security? It’s simple: we want to create a blockchain that EVERYONE trusts. As we discussed previously in this post, if more than one chain existed, users would lose trust, because they would be unable to reasonably determine which chain was the “valid” chain. In order for a group of users to accept the underlying state that is stored on a blockchain, we need a single canonical blockchain that a group of people believes in.
This is exactly what the PoW algorithm does: it ensures that a particular blockchain will remain canonical into the future, making it incredibly difficult for an attacker to create new blocks that overwrite a certain part of history (e.g. by erasing transactions or creating fake transactions) or maintain a fork. To have their block validated first, an attacker would need to consistently solve for the nonce faster than anyone else in the network, such that the network believes their chain is the heaviest chain (based on the principles of the GHOST protocol we mentioned earlier). This would be impossible unless the attacker had more than half of the network mining power, a scenario known as the majority 51% attack.
Image for post
Mining as a wealth distribution mechanism
Beyond providing a secure blockchain, PoW is also a way to distribute wealth to those who expend their computation for providing this security. Recall that a miner receives a reward for mining a block, including:
a static block reward of 5 ether for the “winning’” block (soon to be changed to 3 ether)
the cost of gas expended within the block by the transactions included in the block
an extra reward for including ommers as part of the block
In order to ensure that the use of the PoW consensus mechanism for security and wealth distribution is sustainable in the long run, Ethereum strives to instill these two properties:
Make it accessible to as many people as possible. In other words, people shouldn’t need specialized or uncommon hardware to run the algorithm. The purpose of this is to make the wealth distribution model as open as possible so that anyone can provide any amount of compute power in return for Ether.
Reduce the possibility for any single node (or small set) to make a disproportionate amount of profit. Any node that can make a disproportionate amount of profit means that the node has a large influence on determining the canonical blockchain. This is troublesome because it reduces network security.
In the Bitcoin blockchain network, one problem that arises in relation to the above two properties is that the PoW algorithm is a SHA256 hash function. The weakness with this type of function is that it can be solved much more efficiently using specialized hardware, also known as ASICs.
In order to mitigate this issue, Ethereum has chosen to make its PoW algorithm (Ethhash) sequentially memory-hard. This means that the algorithm is engineered so that calculating the nonce requires a lot of memory AND bandwidth. The large memory requirements make it hard for a computer to use its memory in parallel to discover multiple nonces simultaneously, and the high bandwidth requirements make it difficult for even a super-fast computer to discover multiple nonce simultaneously. This reduces the risk of centralization and creates a more level playing field for the nodes that are doing the verification.
One thing to note is that Ethereum is transitioning from a PoW consensus mechanism to something called “proof-of-stake”.
bitcoin delphi bitcoin x2
bitcoin tx
ethereum проблемы monero криптовалюта bitcoin mac bitcoin обменники arbitrage cryptocurrency bitcoin alert
биржа monero electrum ethereum prune bitcoin bitcoin инструкция криптовалюту monero ethereum php ethereum news siiz bitcoin purse bitcoin bitcoin pizza купить ethereum ethereum asics ethereum перспективы blacktrail bitcoin ethereum токены
monero новости usa bitcoin bitcoin хайпы doge bitcoin ethereum dag ethereum rig car bitcoin bitcoin market Bitcoins can only be created if miners solve a cryptographic puzzle. Since the difficulty of this puzzle increases the amount of computer power the whole miner’s invest, there is only a specific amount of cryptocurrency token that can be created in a given amount of time. This is part of the consensus no peer in the network can break.скачать ethereum
bitcoin protocol bitcoin доходность bitcoin sec новости bitcoin Touchscreen user interfacemine ethereum seed bitcoin bitcoin блог ethereum news This idea of a ledger is the starting point for understanding bitcoin. It is a place to record all transactions that happen in the system, and it is open to and trusted by all system participants. Bitcoin converts this system for recording payments into a currency. Whereas in banking, an account balance represents cash that can be demanded from the bank, what does a unit of bitcoin represent? For now, assume that what is being transacted holds value inherently.monero github киа bitcoin капитализация ethereum apple bitcoin ethereum mine bitcoin взлом bitcoin bank bitcoin central
bitcoin easy cpuminer monero блог bitcoin code bitcoin bitcoin security
rise cryptocurrency бонус bitcoin bitmakler ethereum ubuntu bitcoin bitcoin antminer курс bitcoin bitcoin avto bitcoin daemon bitcoin окупаемость instaforex bitcoin nubits cryptocurrency ethereum calc проверка bitcoin plus500 bitcoin forum bitcoin опционы bitcoin wallets cryptocurrency cryptocurrency forum doubler bitcoin
инструкция bitcoin bitcoin frog рулетка bitcoin ethereum swarm instaforex bitcoin
ethereum форки кошелька ethereum деньги bitcoin bitcoin государство play bitcoin ethereum картинки ropsten ethereum шифрование bitcoin dog bitcoin ethereum биткоин
bitcoin сети полевые bitcoin ethereum client mine ethereum nem cryptocurrency карты bitcoin bitcoin delphi local ethereum delphi bitcoin
лото bitcoin обмен monero bitcoin loans bitcoin сайты ethereum cryptocurrency ethereum кран bitcoin количество go bitcoin
dark bitcoin ethereum обменники bitcoin 123 покупка ethereum
lootool bitcoin bitcoin 2018
заработок ethereum работа bitcoin заработка bitcoin bitcoin formula ethereum russia bitcoin валюта tails bitcoin accelerator bitcoin cold bitcoin panda bitcoin получить bitcoin
monero новости bitcoin адреса
рулетка bitcoin monero курс download bitcoin bitcoin бизнес bitcoin register bitcoin expanse bitcoin 99 bitcoin инвестиции
ethereum swarm bitcoin hunter bitcoin check продать ethereum generator bitcoin
bitcoin капча кошель bitcoin ethereum продам аналитика ethereum bitcoin минфин carding bitcoin cryptocurrency bitcoin indonesia nicehash bitcoin payable ethereum bitcoin grafik bitcoin cash bitcoin people приложение bitcoin half bitcoin рубли bitcoin bitcoin бесплатно bitcoin x gadget bitcoin bitcoin today bitcoin algorithm bitcoin clouding взлом bitcoin
16 bitcoin bitcoin register hourly bitcoin cryptocurrency market ethereum пулы programming bitcoin nya bitcoin приложение tether ethereum wallet bitcoin start будущее ethereum bitcoin заработок
bitcoin python bitcoin отследить
tether кошелек зебра bitcoin bitcoin database monero часы bitcoin bitcoin jp ethereum инвестинг cryptocurrency collector bitcoin ethereum network вывод monero
bitcoin millionaire konverter bitcoin bitcoin get flappy bitcoin bitcoin wallet запрет bitcoin monero usd price bitcoin bitcoin заработок ethereum icon
bitcoin россия майн bitcoin партнерка bitcoin bitcoin paypal
фермы bitcoin ethereum купить bitcoin office my ethereum monero usd ethereum описание wikipedia cryptocurrency bitcoin auto bitcoin torrent bitcoin код серфинг bitcoin konvertor bitcoin перспектива bitcoin ethereum токены bitcoin flapper ico ethereum блокчейна ethereum капитализация bitcoin bitcoin farm 4 bitcoin api bitcoin халява bitcoin Most existing cryptocurrencies, including Bitcoin and Ethereum, have transparent blockchains, meaning that transactions are openly verifiable and traceable by anyone in the world. Furthermore, sending and receiving addresses for these transactions may potentially be linkable to a person's real-world identity.вики bitcoin
service bitcoin global bitcoin
ios bitcoin bitcoin chart смесители bitcoin bitcoin иконка
капитализация bitcoin bitcoin валюты fox bitcoin сервера bitcoin forecast bitcoin
bitcoin joker bitcoin dark транзакции bitcoin платформы ethereum ethereum проект bitcoin wsj
tails bitcoin If you want to learn how to create your cryptocurrency, you’ll need to know how to make a good whitepaper. When I say good, I mean good — a whitepaper is what investors will use to judge your project.карты bitcoin логотип bitcoin обои bitcoin bitcoin mt5 ethereum complexity взлом bitcoin rx560 monero bitcoin plugin gold cryptocurrency криптовалюту monero wikileaks bitcoin bitcoin оплатить bitcoin программирование lazy bitcoin дешевеет bitcoin rus bitcoin обвал ethereum ethereum продам space bitcoin bitcoin опционы bitcoin завести mining bitcoin кран bitcoin film bitcoin bitrix bitcoin bitcoin tx bitcoin конвектор site bitcoin bitcoin гарант bitcoin оборот asrock bitcoin ethereum zcash bounty bitcoin bitcoin майнить chain bitcoin bitcoin автоматический reklama bitcoin tether usb mercado bitcoin bitcoin anonymous love bitcoin bitcoin symbol red bitcoin bitcoin redex ethereum перевод сложность bitcoin bounty bitcoin poloniex monero email bitcoin кран bitcoin cardano cryptocurrency транзакции monero tether app The blockchain Bitcoin uses is supported by a consensus mechanism called 'Proof-of-Work' (PoW). The puzzle is so difficult that no human being could solve it on their own, which is why people need to use their computational power instead.love bitcoin bitcoin стратегия bitcoin primedice For these reasons, we don’t see Ripple as a serious contender for what is toAfter Blockchainbitcoin fortune tether обменник bitcoin future mercado bitcoin bitcoin usd san bitcoin car bitcoin bitcoin payeer mine ethereum iso bitcoin mining bitcoin бизнес bitcoin ethereum ротаторы ava bitcoin майн ethereum bitcoin суть 777 bitcoin создатель ethereum KEY TAKEAWAYSautobot bitcoin ethereum проекты nicehash monero bitcoin доллар life bitcoin bitcoin dollar bitcoin reward bitcoin 2048 Resource Minimizationethereum twitter bitcoin history курсы bitcoin bitcoin genesis bitcoin коды nonce bitcoin daemon monero instaforex bitcoin yandex bitcoin cryptocurrency ico играть bitcoin
mining ethereum ethereum vk bitcoin minergate китай bitcoin tether gps bitcoin андроид boxbit bitcoin chain bitcoin bitcoin carding cryptocurrency wikipedia bitcoin history ethereum casino bitcoin api gui monero monero купить
bitcoin utopia korbit bitcoin cranes bitcoin tether android bitcoin даром plasma ethereum кран bitcoin erc20 ethereum bitcoin broker battle bitcoin ethereum купить hd7850 monero qr bitcoin bitcoin purse 1080 ethereum gas ethereum bitcoin p2p bitcoin torrent логотип bitcoin ethereum install bitcoin войти bitcoin оборот кредит bitcoin airbit bitcoin bitcoin atm monero cpuminer автосборщик bitcoin ethereum создатель bitcoin fpga matteo monero компания bitcoin яндекс bitcoin euro bitcoin wifi tether bitcoin страна tether ico express bitcoin system bitcoin bitcoin значок free ethereum lurkmore bitcoin
p2pool ethereum дешевеет bitcoin cudaminer bitcoin bitcoin status bitcoin doge
bitcoin заработок ethereum scan cryptocurrency ico dollar bitcoin monero wallet wikipedia cryptocurrency air bitcoin bitcoin пулы golden bitcoin
bitcoin fork wirex bitcoin coinmarketcap bitcoin создатель ethereum bitcoin reserve уязвимости bitcoin blacktrail bitcoin car bitcoin виталик ethereum bitcoin crypto bitcoin торговля bitcoin описание отследить bitcoin tradingview bitcoin trade cryptocurrency platinum bitcoin
the ethereum bitcoin nodes
bitcoin de ethereum swarm surf bitcoin card bitcoin продам bitcoin запуск bitcoin хешрейт ethereum wirex bitcoin bitcoin visa bitcoin word wallet tether ethereum zcash ethereum токен калькулятор ethereum decred cryptocurrency matrix bitcoin bitcoin коды remix ethereum maps bitcoin pro bitcoin swiss bitcoin cryptocurrency это падение ethereum
bitcoin network
global bitcoin bitcoin background
planet bitcoin bitcoin магазины the ethereum bitcoin daily bitcoin приват24 bitcoin calculator
bitcoin капча ethereum addresses bitcoin de The final domino to fall, of course, is the power which governments wield over their flock via their ability to print, regulate, and control the nation’s money. When a state currency is challenged, the state itself is challenged, and market forces move swiftly around sickly, depreciating inhibitors. The press conferences of someone like Bernanke would become less and less important, because the currency he printed would be used in narrower and narrower circles. Instead of fighting the government, Bitcoin enables individuals to sidestep it — to ignore it to a large degree. Bitcoin, paired with the internet, provides all that is needed to realize a system of anarcho-capitalism.agario bitcoin local ethereum monero кран
ethereum скачать ethereum история описание bitcoin bitcoin get roll bitcoin clame bitcoin difficulty monero майнить monero bitcoin account порт bitcoin
ethereum io оплатить bitcoin bitcoin legal cryptocurrency exchanges ethereum регистрация bitcoin книги demo bitcoin ethereum график bitcoin торрент neo cryptocurrency ethereum siacoin wallet cryptocurrency брокеры bitcoin bitcoin 2018
сбербанк bitcoin bitcoin котировки bitcoin сколько валюта monero аналоги bitcoin xbt bitcoin monero rub faucet ethereum bitcoin jp bitcoin metatrader bitcoin instaforex bitcoin qiwi bitcoin vpn ethereum 1070
hardware bitcoin bitcoin книга second bitcoin live bitcoin ethereum отзывы bitcoin play bitcoin location
cryptocurrency tech bitcoin проверка monero proxy bitcoin клиент bitcoin click wirex bitcoin технология bitcoin ethereum stratum
bitcoin обозреватель bitcoin вики розыгрыш bitcoin bitcoin xyz компьютер bitcoin bitcoin bow loans bitcoin
сайты bitcoin
bitcoin bbc ethereum swarm
bitcoin технология happy bitcoin bitcoin java loans bitcoin bitcoin china bitcoin monkey ethereum complexity rotator bitcoin bitcoin видеокарты dwarfpool monero ethereum claymore получить bitcoin
биржа ethereum mikrotik bitcoin bitcoin ann bitcoin global bitcoin capital bitcoin cgminer bitcoin capitalization bitcoin visa bitcoin center games bitcoin bitcoin суть bitcoin account my ethereum
обзор bitcoin cryptocurrency wallets bitcoin mt5 king bitcoin
tether js bitcoin location xpub bitcoin coin bitcoin Hashflare Review: Hashflare offers SHA-256 mining contracts and more profitable SHA-256 coins can be mined while automatic payouts are still in BTC. Customers must purchase at least 10 GH/s.litecoin bitcoin bitcoin bitminer ethereum биткоин 1 ethereum If you’ve made it this far, then congratulations! There is still so much more to explain about the system, but at least now you have an idea of the broad outline of the genius of the programming and the concept. For the first time we have a system that allows for convenient digital transfers in a decentralized, trust-free and tamper-proof way. To understand the concept of 'what is a smart contract?' consider the purchase of a chocolate bar from a vending machine. The buyer deposits change then presses the button corresponding to the selection. That button, mapped against that particular slot, activates a lever in the machine to push out the candy. The transaction occurred without the need for a cashier or clerk. A smart contract is similar to a vending machine in that it eliminates the need for an intermediary. In this case, the vending machine is replacing a direct seller and allowing the consumer to make a purchase without a middleman.bitcoin phoenix эмиссия ethereum monero node крах bitcoin monero asic cryptocurrency charts кости bitcoin electrum bitcoin monero курс bitcoin бонус 1080 ethereum bitcoin биржа bitcoin пул monero кран перевод ethereum ethereum web3 cryptocurrency all cryptocurrency
арестован bitcoin What Is Bitcoin?сложность ethereum сборщик bitcoin unconfirmed bitcoin bitcoin хабрахабр bitcoin прогнозы криптовалюту bitcoin ethereum coin продам ethereum bitcoin сатоши bitcoin graph bitcoin коллектор перевод ethereum
пожертвование bitcoin bitcoin майнер multiply bitcoin bitcoin change forum ethereum 1 monero трейдинг bitcoin testnet ethereum hub bitcoin bitcoin софт 99 bitcoin обои bitcoin