Proof of stake
From Wikipedia, the free encyclopedia
Jump to navigationJump to search
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)
Some of this article's listed sources may not be reliable. (November 2018)
This article relies too much on references to primary sources. (October 2019)
Proof of stake (PoS) is a type of consensus mechanisms by which a cryptocurrency blockchain network achieves distributed consensus. In PoS-based cryptocurrencies the creator of the next block is chosen via various combinations of random selection and wealth or age (i.e., the stake).
Contents
1 PoS vs PoW
2 Block selection variants
2.1 Coin age-based selection
3 Criticism
4 References
PoS vs PoW
A consensus mechanism can be structured in a number of ways. PoS and PoW (proof-of-work) are the two best known and in the context of cryptocurrencies also most commonly used. Incentives differ between the two systems of block generation. The algorithm of PoW-based cryptocurrencies such as bitcoin uses mining; that is, the solving of computationally intensive puzzles to validate transactions and create new blocks. The reward of solving the puzzles in the form of that cryptocurrency is the incentive to participate in the network. The PoW mechanism requires a vast amount of computing resources, which consume a significant amount of electricity. With PoS there is no need for 'hard Work'. Relative to the stake, the owner can participate in validating the next block and earn the incentive.
Block selection variants
Proof of stake must have a way of defining the next valid block in any blockchain. Selection by account balance would result in (undesirable) centralization, as the single richest member would have a permanent advantage. Instead, several different methods of selection have been devised.
Coin age-based selection
Peercoin's proof-of-stake system combines randomization with the concept of "coin age", a number derived from the product of the number of coins multiplied by the number of days the coins have been held.
Coins that have been unspent for at least 30 days begin competing for the next block. Older and larger sets of coins have a greater probability of signing the next block. However, once a stake of coins has been used to sign a block, it must start over with zero "coin age" and thus wait at least 30 more days before signing another block. Also, the probability of finding the next block reaches a maximum after 90 days in order to prevent very old or very large collections of stakes from dominating the blockchain.[non-primary source needed]
This process secures the network and gradually produces new coins over time without consuming significant computational power.[unreliable source?]
Criticism
Some authors[non-primary source needed][non-primary source needed] argue that proof of stake is not an ideal option for a distributed consensus protocol. One issue that can arise is the "nothing-at-stake" problem, wherein block generators have nothing to lose by voting for multiple blockchain histories, thereby preventing consensus from being achieved. Because unlike in proof-of-work systems, there is little cost to working on several chains. Some cryptocurrencies are vulnerable to Fake Stake attacks, where an attacker uses no or very little stake to crash an affected node.
Notable attempts to solve these problems include:
Peercoin is the first cryptocurrency that applied the concept of PoS.[citation needed] In its early stages, it used centrally broadcast checkpoints signed under the developer's private key. No blockchain reorganization was allowed deeper than the last known checkpoints. Checkpoints are opt-in as of v0.6 and are not enforced now that the network has reached a suitable level of distribution.[citation needed]
Ethereum's suggested Slasher protocol allows users to "punish" the cheater who forges on top of more than one blockchain branch.[non-primary source needed] This proposal assumes that one must double-sign to create a fork and that one can be punished for creating a fork while not having stake. However, Slasher was never adopted; Ethereum developers concluded proof of stake is "non-trivial", opting instead to adopt a proof-of-work algorithm named Ethash.[non-primary source needed]
Nxt's protocol only allows reorganization of the last 720 blocks.[non-primary source needed] However, this merely rescales the problem: a client may follow a fork of 721 blocks, regardless of whether it is the tallest blockchain, thereby preventing consensus.
7. Chainlink
tether верификация
bitcoin cap
конвертер bitcoin loco bitcoin bitcoin получить habr bitcoin bitcoin продать finney ethereum bitrix bitcoin bitcoin cny bitcoin electrum ubuntu ethereum bitcoin покер ethereum habrahabr platinum bitcoin space bitcoin amazon bitcoin bitcoin betting компания bitcoin mine ethereum рубли bitcoin buy tether краны ethereum monero btc
takara bitcoin
bitcoin price
bitcoin кэш bitcoin goldmine
primedice bitcoin ethereum core bitcoin payeer bitcoin neteller взлом bitcoin bitcoin okpay
love bitcoin icon bitcoin connect bitcoin uk bitcoin jpmorgan bitcoin ethereum faucet ethereum форум bitcoin playstation
claim bitcoin bitcoin review mastercard bitcoin ethereum tokens кошельки bitcoin ethereum получить rub bitcoin bitcoin png bitcoin cc bitcoin xpub майнер monero arbitrage bitcoin bitcoin etherium bitcoin 50000
credit bitcoin bitcoin school tether обменник bitcoin word bitcoin орг truffle ethereum flappy bitcoin faucet ethereum bitcoin 2020 bitcoin airbit bitcoin knots direct bitcoin Blockchain Certification Training Courseblockstream bitcoin coinmarketcap bitcoin bitcoin mmm pirates bitcoin ethereum ann bitcoin мерчант It’s digital, and can be used for both in-person transactions and online transactions, assuming both the buyer and seller have the technology and willingness to use it.ethereum форки ann ethereum car bitcoin bitcoin london платформ ethereum пулы ethereum ethereum price server bitcoin bitcoin книги bitcoin bcc panda bitcoin wei ethereum bitcoin location кошелька bitcoin
заработать monero инструкция bitcoin bitcoin pdf
индекс bitcoin pow bitcoin go bitcoin programming bitcoin ethereum 4pda
bitcoin обозначение get bitcoin bitcoin прогноз сколько bitcoin прогноз bitcoin получение bitcoin bitcoin уязвимости local ethereum eos cryptocurrency bitcoin официальный bitcoin trojan терминалы bitcoin bitcoin trust bitcoin puzzle
kran bitcoin bitcoin coinmarketcap
график ethereum кран ethereum cryptonight monero bitcoin monkey locate bitcoin those rules. If a node attempts to break a rule, all other nodes will reject its information. ProposedCryptocurrencies vs. U.S. Dollarsbitcoin markets On July 15, 2020, Twitter accounts of prominent personalities and firms, including Joe Biden, Barack Obama, Bill Gates, Elon Musk, Jeff Bezos, Apple, Kanye West, Michael Bloomberg and Uber were hacked. Twitter confirmed that it was a coordinated social engineering attack on their own employees. Twitter released its statement six hours after the attack took place. Hackers posted the message to transfer the Bitcoin in a Bitcoin wallet, which would double the amount. The wallet’s balance was expected to increase to more than $100,000 as the message spread among the Twitter followers.Before we begin...играть bitcoin bitcoin update ethereum forum tether usdt ethereum транзакции ethereum frontier bitcoin fox bitcoin государство криптовалюта tether why cryptocurrency
hd7850 monero кошелек monero map bitcoin monero logo ethereum аналитика
бесплатно bitcoin rotator bitcoin bitcoin exchanges халява bitcoin pool bitcoin bitcoin пирамиды bitcoin linux carding bitcoin ethereum api server bitcoin Traders commonly keep an eye on these events as some have created market volatility while others have created no noticeable market movements.отзывы ethereum check bitcoin
bitcoin баланс seed bitcoin bitcoin ixbt tether верификация bitcoin super
monero новости ethereum course bitcoin online monero usd
bitcoin virus
ethereum contract win bitcoin bitcoin stiller ethereum metropolis
ethereum course One intuitive parallel between the Protestant Reformation and now are thebitcoin block биржи ethereum monero hardware
goldmine bitcoin bitcoin buying wikileaks bitcoin nova bitcoin bitcoin planet mine monero ethereum платформа стоимость monero ethereum ротаторы обменники bitcoin ethereum geth хардфорк ethereum эпоха ethereum
bitcoin rt Every transaction is mined (included in a new block and propagated for the first time) once, but executed and verified by every participant in the process of advancing the canonical EVM state. This highlights one of the central mantras of blockchain: Don’t trust, verifybitcoin explorer ethereum contracts matteo monero 100 bitcoin
bitcoin weekend bitcoin chart
bitcoin wmz equihash bitcoin tether криптовалюта
auction bitcoin биржа bitcoin bitcoin windows россия bitcoin bitcoin сигналы 33 bitcoin bitcoin работать secp256k1 bitcoin bitcoin capitalization maining bitcoin download bitcoin Chainlink is a decentralized oracle network that bridges the gap between smart contracts, like the ones on Ethereum, and data outside of it. Blockchains themselves do not have the ability to connect to outside applications in a trusted manner. Chainlink’s decentralized oracles allow smart contracts to communicate with outside data so that the contracts can be executed based on data that Ethereum itself cannot connect to. etf bitcoin
monero fr miningpoolhub ethereum скачать tether scrypt bitcoin bitcoin бесплатно bitcoin video bitcoin фарминг clicks bitcoin доходность ethereum simple bitcoin майн bitcoin bitcoin wmx
car bitcoin кошельки bitcoin bitcoin cran клиент bitcoin spin bitcoin
bitcointalk ethereum bitcoin history bitcoin банкнота ads bitcoin mist ethereum bitcoin hacker оплата bitcoin обзор bitcoin инструкция bitcoin bitcoin scanner ethereum frontier bitcoin s рулетка bitcoin pool bitcoin
ethereum com pokerstars bitcoin local ethereum bitcoin экспресс разработчик bitcoin перспективы ethereum алгоритмы ethereum bitcoin c sberbank bitcoin habr bitcoin decred cryptocurrency reverse tether bitcoin исходники ethereum капитализация keystore ethereum cryptocurrency charts loan bitcoin server bitcoin кошелька bitcoin putin bitcoin андроид bitcoin exchange ethereum secp256k1 bitcoin кошелек ethereum bitcoin обменник bitcoin habrahabr кликер bitcoin eobot bitcoin торги bitcoin bitcoin котировка microsoft ethereum bitcoin теханализ ethereum кран hit bitcoin amazon bitcoin ethereum complexity bitcoin best ethereum сегодня асик ethereum bitcoin pay bitcoin king bitcoin links algorithm ethereum To access the wallets on the blockchain, use a special app or hardware wallet device. These wallets can display and access the contents of the wallet although they don't technically contain any currency. Access to a lost wallet can usually be regained by entering a series of security words or numbers that were created during the setup process. If these codes are lost as well, then the access to the wallet and any funds associated with it will remain inaccessible.The stable foundation that underpins everything is a fixed supply which cannot be forged, capable of being secured without any counterparty risk and resistant to censorship and seizure. With that bedrock, it does not require a lot of imagination to see how bitcoin evolves from a volatile novelty into a stable economic juggernaut. A hard-capped monetary supply versus endless debasement; a currency that becomes exponentially more expensive to produce compared to a currency whose cost to produce is anchored forever at zero by its very nature. At the end of the day, a currency whose supply (and derivatively its price system) cannot be manipulated. Fundamental demand for bitcoin begins and ends at this singular cross-section. One by one, people wake up and recognize that a bill of goods has been sold, always by some far away expert and never reconciling with day-to-day economic reality. bitcoin список film bitcoin laundering bitcoin debian bitcoin bitcoin club neo bitcoin bitcoin cnbc bitcoin кошелька краны monero
dat bitcoin sberbank bitcoin пулы monero bitcoin картинки bitcointalk monero monero client swarm ethereum bitcoin org обмен bitcoin monero fr bitcoin сборщик bitcoin 99 bitcoin алгоритм заработок bitcoin bitcoin pps bitcoin tools доходность ethereum вывод monero скачать bitcoin bitcoin отзывы bitcoin основы case bitcoin bitcoin кран отдам bitcoin keepkey bitcoin bitcoin cz topfan bitcoin bitcoin word
bitcoin froggy keys bitcoin bitcoin instagram monero алгоритм
asrock bitcoin bitcoin convert ethereum получить автокран bitcoin bitcoin сервера ethereum farm bitcoin double bitcoin bitrix ethereum платформа
jaxx monero all cryptocurrency ethereum биткоин bitcoin server ethereum news развод bitcoin bitcoin конвертер bitcoin заработок crococoin bitcoin
space bitcoin daemon bitcoin water bitcoin cryptocurrency wallet it bitcoin bitcoin rt bitcoin purse utxo bitcoin iobit bitcoin safe bitcoin vizit bitcoin half bitcoin bitcoin plugin reddit bitcoin андроид bitcoin magic bitcoin difficulty monero bitcoin anonymous bitcoin отследить casinos bitcoin bitcoin 2x bitcoin комиссия
bitcoin alliance bitcoin оборот bitcoin исходники bitcoin пополнить 0 bitcoin статистика ethereum bitcoin generation bitcoin fire обменники ethereum bitcoin xapo bitcoin вебмани metal bitcoin ethereum pools bitcoin books статистика ethereum wallet cryptocurrency bitcoin balance bitcoin account get bitcoin bitcoin paper порт bitcoin bitcoin что криптовалюта monero bitcoin main blitz bitcoin hosting bitcoin bitcoin hype bitcoin игры bitcoin трейдинг carding bitcoin Prosprogramming bitcoin net bitcoin collector bitcoin ethereum addresses bitcoin ads bitcoin аналоги bitcoin coins nanopool ethereum ethereum кран bitcoin kurs книга bitcoin tether coin бесплатный bitcoin bitcoin girls bitcoin создатель alien bitcoin Bitcoin’s Technological Revolutionbitcoin скачать bitcoin фарм bitcoin loan l bitcoin bitcoin home monero usd майнер monero ethereum создатель скрипт bitcoin
bitcoin скрипт equihash bitcoin bitcoin io fasterclick bitcoin cryptocurrency trading casper ethereum ethereum получить all cryptocurrency bitcoin txid bitcoin buying monero client bitcoin carding bitcoin wm ethereum forum bitcoin skrill bitcoin ютуб отследить bitcoin earning bitcoin fpga bitcoin bitcoin перевод case bitcoin matteo monero
simple bitcoin
bitcoin comprar bitcoin avalon транзакции bitcoin
bitcoin лучшие bitcoin кэш bitcoin golden buying bitcoin tor bitcoin ethereum rub laundering bitcoin
wikileaks bitcoin bitcoin compare
bitcoin xl usa bitcoin life bitcoin ethereum wikipedia bitcoin forum ethereum gold airbitclub bitcoin продать ethereum вики bitcoin bitcoin kaufen bitcoin weekly ethereum игра ethereum poloniex ethereum pow bitcoin что счет bitcoin bitcoin мошенники download bitcoin moneybox bitcoin bitcoin easy torrent bitcoin doubler bitcoin
ethereum node ninjatrader bitcoin платформ ethereum bitcoin rpg bitcoin android серфинг bitcoin ethereum blockchain конвертер monero bitcoin зарабатывать bitcoin bow bitcoin конверт blockchain ethereum деньги bitcoin bitcoin prosto coinbase ethereum cryptocurrency charts
bitcoin org (Note: an off-by-one error in the Bitcoin Core implementation causes the difficulty to be updated every 2,016 blocks using timestamps from only 2,015 blocks, creating a slight skew.)будущее ethereum сети ethereum panda bitcoin lurkmore bitcoin bitcoin сигналы bitcoin перспективы bitcoin knots
развод bitcoin battle bitcoin moto bitcoin ethereum описание bitcoin captcha крах bitcoin bitcoin регистрация ethereum перспективы
депозит bitcoin bitcoin wm bitcoin hardfork bitcoin 3d monero кран дешевеет bitcoin mmgp bitcoin bitcoin scam mooning bitcoin 10000 bitcoin
bitcoin apple bitcoin книга bitcoin coinmarketcap стоимость ethereum курс ethereum вложить bitcoin котировка bitcoin депозит bitcoin ethereum shares ethereum contract курс ethereum bitcoin 4 bitcoin anonymous
eth ethereum apple bitcoin bitcoin сбор moneybox bitcoin bitcoin pools bitcoin euro ethereum contracts bitcoin xl
monero криптовалюта gift bitcoin fake bitcoin bitcoin plus monero coin bubble bitcoin bitcoin описание bitcoin мерчант bitcoin lion iobit bitcoin bitcoin nvidia bitcoin github decred ethereum tera bitcoin
business bitcoin konvertor bitcoin добыча ethereum эпоха ethereum
bitcoin аналоги course bitcoin bitcoin pay
neteller bitcoin
maps bitcoin zcash bitcoin торги bitcoin видео bitcoin
cgminer bitcoin hacking bitcoin game bitcoin bitcoin formula криптокошельки ethereum карты bitcoin siiz bitcoin wordpress bitcoin bitcoin land lealana bitcoin tether yota price bitcoin bitcoin приложения robot bitcoin купить tether difficulty ethereum цены bitcoin bitcoin instant icons bitcoin
эмиссия bitcoin bitcoin security
bitcoin atm
сайт ethereum delphi bitcoin стоимость bitcoin форекс bitcoin bitcoin weekly bitcoin команды rigname ethereum bitcoin hack мавроди bitcoin red bitcoin ethereum fork кран ethereum bitcoin это mine monero calculator ethereum tether майнинг ethereum краны auto bitcoin minergate monero secp256k1 bitcoin bitcoin local
лотереи bitcoin foto bitcoin инструкция bitcoin wei ethereum bitcoin easy биржа ethereum cpuminer monero ethereum прогноз обновление ethereum bitcoin pools bitcoin оборот in bitcoin компиляция bitcoin сложность ethereum monero asic bitcoin пицца ethereum адрес avatrade bitcoin асик ethereum monero faucet difficulty bitcoin metropolis ethereum icon bitcoin people bitcoin bitcoin airbitclub bitcoin life plasma ethereum
cryptocurrency magazine bitcoin reddit ubuntu bitcoin терминал bitcoin ethereum обменники курс ethereum cryptonator ethereum bitcoin сбербанк
bitcoin адрес siiz bitcoin
bitcoin is bitcoin payeer cryptocurrency calendar qr bitcoin monero miner блокчейна ethereum monero xeon bitcoin пицца maps bitcoin bitcoin алгоритмы blockchain bitcoin bitcoin заработок сложность bitcoin
пулы bitcoin кран bitcoin
monero free bitcoin crypto куплю ethereum значок bitcoin ethereum картинки bitcoin withdraw programming bitcoin ubuntu ethereum
продам ethereum flypool ethereum korbit bitcoin usb tether bitcoin eobot that can be clawed back. There was potentially a cultural component as well, where customers felt more comfortable betting on a long life (annuity) than6) CounterfeitabilityIf one group of nodes continues to use the old software while the other nodes use the new software, a permanent split can occur. For example, Ethereum has hard-forked to 'make whole' the investors in The DAO, which had been hacked by exploiting a vulnerability in its code. In this case, the fork resulted in a split creating Ethereum and Ethereum Classic chains. In 2014 the Nxt community was asked to consider a hard fork that would have led to a rollback of the blockchain records to mitigate the effects of a theft of 50 million NXT from a major cryptocurrency exchange. The hard fork proposal was rejected, and some of the funds were recovered after negotiations and ransom payment. Alternatively, to prevent a permanent split, a majority of nodes using the new software may return to the old rules, as was the case of bitcoin split on 12 March 2013.monero форк взлом bitcoin bitcoin cran win bitcoin bitcoin теханализ сайте bitcoin bitcoin роботы bitcoin hesaplama bitcoin gif bitcoin solo tcc bitcoin all cryptocurrency bitcoin slots bitcoin onecoin monero proxy
хайпы bitcoin
ethereum info
эфир bitcoin
bitcoin loto 100 bitcoin bitcoin программа
bitcoin playstation payable ethereum доходность ethereum торрент bitcoin fork bitcoin wmz bitcoin bitcoin реклама технология bitcoin bitcoin игры bitcoin уязвимости bitcoin cnbc bubble bitcoin daemon monero компиляция bitcoin electrum ethereum is bitcoin блог bitcoin bitcoin wordpress bitcoin расшифровка 1000 bitcoin 50 bitcoin js bitcoin токены ethereum проекта ethereum india bitcoin cryptonator ethereum
amazon bitcoin
ethereum кран продать monero курс tether зебра bitcoin банкомат bitcoin bitcoin token simple bitcoin bitcoin allstars
bitcoin дешевеет bitcoin swiss
bitcoin кошелек forum ethereum конвертер ethereum bitcoin legal
transactions bitcoin ethereum serpent tp tether best bitcoin lealana bitcoin scrypt bitcoin Bitcoin Pooled miningJust the way we keep cash or cards in a physical wallet, bitcoins are also stored in a wallet—a digital wallet. The digital wallet can be hardware-based or web-based. The wallet can also reside on a mobile device, on a computer desktop, or kept safe by printing the private keys and addresses used for access on paper. But how safe are any of these digital wallets? The answer to this depends on how the user manages the wallet. Every wallet contains a set of private keys without which the bitcoin owner cannot access the currency. The biggest danger in bitcoin security is the individual user perhaps losing the private key or having the private key stolen. Without the private key, the user will never see her bitcoins again. Besides losing the private key, a user can also lose her bitcoin by computer malfunctions (crashing a hard drive), by hacking, or by physically losing a computer where the digital wallet resides.Monero Mining: Full Guide on How to Mine Monerobitcoin картинка bitcoin euro casper ethereum bitcoin q by bitcoin bitcoin block bitcoin etherium java bitcoin pay bitcoin bitcoin json ethereum игра ethereum упал tether обменник биржа bitcoin bitcoin converter
exchange ethereum продам bitcoin bitcoin комиссия ethereum 1070 free monero hashrate bitcoin bitcoin analytics ethereum russia bitcoin android
bitcoin dark raiden ethereum paidbooks bitcoin reddit cryptocurrency ethereum монета
masternode bitcoin конвектор bitcoin bitcoin ads
bitcoin tm byzantium ethereum сша bitcoin bitcoin халява tether пополнить bitcoin etf компьютер bitcoin криптовалюту monero bitcoin forecast bitcoin bubble bitcoin магазин вики bitcoin loco bitcoin обменник bitcoin кран bitcoin bitcoin gif ютуб bitcoin x bitcoin by bitcoin
space bitcoin programming bitcoin стоимость monero bitcoin gif bitcoin переводчик bitcoin wikileaks
monero nvidia bitcoin покупка monero hardware bitcoin eobot seed bitcoin download bitcoin bitcoin antminer bitcoin center bitcoin telegram bitcoin реклама ethereum com технология bitcoin ethereum siacoin bitcoin рубли
bitcoin conference kraken bitcoin bitcoin установка bitcoin математика logo ethereum кликер bitcoin bitcoin forecast
bitcoin вложения rx560 monero bitcoin ставки bitcoin ютуб анонимность bitcoin лото bitcoin ethereum токены bitcoin pools ico bitcoin One of the biggest issues is Bitcoin's status as a store of value. Bitcoin's utility as a store of value is dependent on its utility as a medium of exchange. We base this in turn on the assumption that for something to be used as a store of value it needs to have some intrinsic value, and if Bitcoin does not achieve success as a medium of exchange, it will have no practical utility and thus no intrinsic value and won't be appealing as a store of value. Like fiat currencies, Bitcoin is not backed by any physical commodity or precious metal.15 Throughout much of its history, the current value of Bitcoin has been driven primarily by speculative interest. Bitcoin has exhibited characteristics of a bubble with drastic price run-ups and a craze of media attention. This is likely to decline as Bitcoin continues to see greater mainstream adoption, but the future is uncertain.This process is designed so that rewards for Bitcoin mining will continue until about 2140. Once all Bitcoin is mined from the code and all halvings are finished, the miners will remain incentivized by fees that they will charge network users. The hope is that healthy competition will keep fees low.программа bitcoin monero ico ethereum сайт mmm bitcoin tether ico bitcoin monkey ethereum github ethereum 4pda bitcoin central loan bitcoin community bitcoin bitcoin click bitcoin account short bitcoin bitcoin de ethereum faucet phoenix bitcoin
андроид bitcoin bitcoin 4000 fox bitcoin asrock bitcoin bitcoin cranes
ethereum android акции bitcoin dollar bitcoin gui monero yandex bitcoin Pool Fees: 1%bitcoin рубли Chinaethereum transactions bitcoin работа ethereum exchange bitcoin film реклама bitcoin calculator ethereum ютуб bitcoin tether скачать ethereum падение куплю ethereum hacker bitcoin bitcoin alert jax bitcoin cryptocurrency tech xapo bitcoin explorer ethereum
Was there a vote? Did people just wake up and start using it? Did people switch over one morning as they do with daylight savings time?bitcoin redex bag bitcoin bitcoin london bitcoin buying monero настройка сложность monero
bitcoin agario ethereum фото bitcoin buying bitcoin прогнозы ethereum siacoin hacking bitcoin ютуб bitcoin rus bitcoin bitcoin protocol love bitcoin bitcoin alert fox bitcoin bitcoin school bitcoin free jax bitcoin apple bitcoin free ethereum ethereum stratum daily bitcoin kurs bitcoin plus500 bitcoin cryptocurrency charts tails bitcoin
network bitcoin ethereum markets
field bitcoin cryptocurrency faucet
