Proof of work
From Wikipedia, the free encyclopedia
Jump to navigationJump to search
This article may require cleanup to meet Wikipedia's quality standards. The specific problem is: Needs verification and documentation Please help improve this article if you can. (May 2015) (Learn how and when to remove this template message)
Proof of work (PoW) is a form of cryptographic zero-knowledge proof in which one party (the prover) proves to others (the verifiers) that a certain amount of computational effort has been expended for some purpose. Verifiers can subsequently confirm this expenditure with minimal effort on their part. The concept was invented by Cynthia Dwork and Moni Naor in 1993 as a way to deter denial-of-service attacks and other service abuses such as spam on a network by requiring some work from a service requester, usually meaning processing time by a computer. The term "proof of work" was first coined and formalized in a 1999 paper by Markus Jakobsson and Ari Juels. Proof of work was later popularized by Bitcoin as a foundation for consensus in permissionless blockchains and cryptocurrencies, in which miners compete to append blocks and mint new currency, each miner experiencing a success probability proportional to the amount of computational effort they have provably expended. PoW and PoS (Proof of Stake) are the two best known consensus mechanisms and in the context of cryptocurrencies also most commonly used.
A key feature of proof-of-work schemes is their asymmetry: the work must be moderately hard (yet feasible) on the prover or requester side but easy to check for the verifier or service provider. This idea is also known as a CPU cost function, client puzzle, computational puzzle, or CPU pricing function. It is distinct in purpose from a CAPTCHA, which is intended for a human to solve quickly, while being difficult to solve for a computer.
Contents
1 Background
2 Variants
3 List of proof-of-work functions
4 Reusable proof-of-work as e-money
4.1 Bitcoin-type proof of work
4.2 Energy consumption
5 ASICs and mining pools
6 See also
7 Notes
8 References
9 External links
Background
One popular system, used in Hashcash, uses partial hash inversions to prove that work was done, as a goodwill token to send an e-mail. For instance, the following header represents about 252 hash computations to send a message to calvin@comics.net on January 19, 2038:
X-Hashcash: 1:52:380119:calvin@comics.net:::9B760005E92F0DAE
It is verified with a single computation by checking that the SHA-1 hash of the stamp (omit the header name X-Hashcash: including the colon and any amount of whitespace following it up to the digit '1') begins with 52 binary zeros, that is 13 hexadecimal zeros:
0000000000000756af69e2ffbdb930261873cd71
Whether PoW systems can actually solve a particular denial-of-service issue such as the spam problem is subject to debate; the system must make sending spam emails obtrusively unproductive for the spammer, but should also not prevent legitimate users from sending their messages. In other words, a genuine user should not encounter any difficulties when sending an email, but an email spammer would have to expend a considerable amount of computing power to send out many emails at once. Proof-of-work systems are being used as a primitive by other more complex cryptographic systems such as bitcoin which uses a system similar to Hashcash.
Variants
There are two classes of proof-of-work protocols.
Challenge–response protocols assume a direct interactive link between the requester (client) and the provider (server). The provider chooses a challenge, say an item in a set with a property, the requester finds the relevant response in the set, which is sent back and checked by the provider. As the challenge is chosen on the spot by the provider, its difficulty can be adapted to its current load. The work on the requester side may be bounded if the challenge-response protocol has a known solution (chosen by the provider), or is known to exist within a bounded search space.
Proof of Work challenge response.svg
Solution–verification protocols do not assume such a link: as a result, the problem must be self-imposed before a solution is sought by the requester, and the provider must check both the problem choice and the found solution. Most such schemes are unbounded probabilistic iterative procedures such as Hashcash.
Proof of Work solution verification.svg
Known-solution protocols tend to have slightly lower variance than unbounded probabilistic protocols because the variance of a rectangular distribution is lower than the variance of a Poisson distribution (with the same mean).[further explanation needed] A generic technique for reducing variance is to use multiple independent sub-challenges, as the average of multiple samples will have a lower variance.
There are also fixed-cost functions such as the time-lock puzzle.
Moreover, the underlying functions used by these schemes may be:
CPU-bound where the computation runs at the speed of the processor, which greatly varies in time, as well as from high-end server to low-end portable devices.
Memory-bound where the computation speed is bound by main memory accesses (either latency or bandwidth), the performance of which is expected to be less sensitive to hardware evolution.
Network-bound if the client must perform few computations, but must collect some tokens from remote servers before querying the final service provider. In this sense, the work is not actually performed by the requester, but it incurs delays anyway because of the latency to get the required tokens.
Finally, some PoW systems offer shortcut computations that allow participants who know a secret, typically a private key, to generate cheap PoWs. The rationale is that mailing-list holders may generate stamps for every recipient without incurring a high cost. Whether such a feature is desirable depends on the usage scenario.
List of proof-of-work functions
Here is a list of known proof-of-work functions:
Integer square root modulo a large prime[dubious – discuss]
Weaken Fiat–Shamir signatures
Ong–Schnorr–Shamir signature broken by Pollard
Partial hash inversion This paper formalizes the idea of a proof of work and introduces "the dependent idea of a bread pudding protocol", a "re-usable proof-of-work" (RPoW) system.
Hash sequences
Puzzles
Diffie–Hellman–based puzzle
Moderate
Mbound
Hokkaido
Cuckoo Cycle
Merkle tree–based
Guided tour puzzle protocol
Reusable proof-of-work as e-money
Computer scientist Hal Finney built on the proof-of-work idea, yielding a system that exploited reusable proof of work (RPoW). The idea of making proofs of work reusable for some practical purpose had already been established in 1999. Finney's purpose for RPoW was as token money. Just as a gold coin's value is thought to be underpinned by the value of the raw gold needed to make it, the value of an RPoW token is guaranteed by the value of the real-world resources required to 'mint' a PoW token. In Finney's version of RPoW, the PoW token is a piece of Hashcash.
A website can demand a PoW token in exchange for service. Requiring a PoW token from users would inhibit frivolous or excessive use of the service, sparing the service's underlying resources, such as bandwidth to the Internet, computation, disk space, electricity, and administrative overhead.
Finney's RPoW system differed from a PoW system in permitting the random exchange of tokens without repeating the work required to generate them. After someone had "spent" a PoW token at a website, the website's operator could exchange that "spent" PoW token for a new, unspent RPoW token, which could then be spent at some third-party website similarly equipped to accept RPoW tokens. This would save the resources otherwise needed to 'mint' a PoW token. The anti-counterfeit property of the RPoW token was guaranteed by remote attestation. The RPoW server that exchanges a used PoW or RPoW token for a new one of equal value uses remote attestation to allow any interested party to verify what software is running on the RPoW server. Since the source code for Finney's RPoW software was published (under a BSD-like license), any sufficiently knowledgeable programmer could, by inspecting the code, verify that the software (and, by extension, the RPoW server) never issued a new token except in exchange for a spent token of equal value.
Until 2009, Finney's system was the only RPoW system to have been implemented; it never saw economically significant use.
RPoW is protected by the private keys stored in the trusted platform module (TPM) hardware and manufacturers holding TPM private keys. Stealing a TPM manufacturer's key or obtaining the key by examining the TPM chip itself would subvert that assurance.
Bitcoin-type proof of work
In 2009, the Bitcoin network went online. Bitcoin is a proof-of-work cryptocurrency that, like Finney's RPoW, is also based on the Hashcash PoW. But in Bitcoin, double-spend protection is provided by a decentralized P2P protocol for tracking transfers of coins, rather than the hardware trusted computing function used by RPoW. Bitcoin has better trustworthiness because it is protected by computation. Bitcoins are "mined" using the Hashcash proof-of-work function by individual miners and verified by the decentralized nodes in the P2P bitcoin network.
The difficulty is periodically adjusted to keep the block time around a target time.
Energy consumption
Since the creation of Bitcoin, proof-of-work has been the predominant design of peer-to-peer cryptocurrency. Many studies have been looking at the energy consumption of mining. The PoW mechanism requires a vast amount of computing resources, which consume a significant amount of electricity. Bitcoin's energy consumption can power an entire country.
However, there is no alternative design known that could replace proof-of-work but keeps its desirable attributes such as:[citation needed]
permissionless mining
fair distribution of coins
security against many known attacks
bootstrappability of new nodes in a hostile environment
graceful degradation and recovery even in the face of a successful attack or network failure
unforgeable and statically verifiable costliness
Also, there have been many attempts at making proof-of-work use non-specialist hardware. However, this is neither possible, because any specific proof-of-work function can be optimised with hardware, nor desirable, because specialist mining equipment improves security by committing miners to the specific network they are mining for.[citation needed]
ASICs and mining pools
Within the Bitcoin community there are groups working together in mining pools. Some miners use application-specific integrated circuits (ASICs) for PoW. This trend toward mining pools and specialized ASICs has made mining some cryptocurrencies economically infeasible for most players without access to the latest ASICs, nearby sources of inexpensive energy, or other special advantages.
Some PoWs claim to be ASIC-resistant, i.e. to limit the efficiency gain that an ASIC can have over commodity hardware, like a GPU, to be well under an order of magnitude. ASIC resistance has the advantage of keeping mining economically feasible on commodity hardware, but also contributes to the corresponding risk that an attacker can briefly rent access to a large amount of unspecialized commodity processing power to launch a 51% attack against a cryptocurrency.
ethereum claymore flappy bitcoin bitcoin софт фермы bitcoin bestchange bitcoin bitcoin c создать bitcoin bitcoin gadget конвектор bitcoin ico cryptocurrency bitcoin aliens обменник ethereum
bitcoin asic
ethereum курс ethereum хешрейт bitcoin blog
форки ethereum bye bitcoin платформе ethereum валюта bitcoin pay bitcoin перспективы ethereum bitcoin script spin bitcoin A total of 262,144 validators is needed at minimum for Eth 2.0 to advance to its next phase of development in which 64 mini-blockchains, called 'shards,' will be spawned. At the current rate of 900 new validators being added to the network each day, phase 1 will occur sometime in late August or early September of this year. crococoin bitcoin
Wikimedia / Public Domainbitcoin cap bitcoin click программа tether accepts bitcoin форк bitcoin coinmarketcap bitcoin рост bitcoin today bitcoin
monero freebsd bitcoin nodes fpga ethereum bitcoin skrill bitcoin price банкомат bitcoin bitcoin 1070 капитализация ethereum казино bitcoin bitcoin таблица обменять monero
wmx bitcoin обменять ethereum подтверждение bitcoin
bitcoin china bitcoin metal
ethereum online сложность ethereum bitcoin сатоши майнинга bitcoin bitcoin faucet часы bitcoin
coingecko bitcoin
monero обменять bitcoin mixer bitcoin деньги ethereum заработок bitcoin форекс monero сложность вход bitcoin bitcoin check accepts bitcoin адреса bitcoin андроид bitcoin casper ethereum
bitcoin nasdaq ethereum упал
ethereum supernova
компания bitcoin bitcoin trade нода ethereum bitcoin майнер bitcoin pps bitcoin рубли credit bitcoin теханализ bitcoin bitcoin рухнул cryptocurrency gold p2p bitcoin ethereum com ethereum markets ethereum сложность express bitcoin анимация bitcoin statistics bitcoin
tera bitcoin monero купить ethereum io cryptocurrency news bitcoin atm bitcoin pizza bitcoin microsoft хабрахабр bitcoin динамика ethereum bitcoin adress bitcoin king bitcoin knots кредит bitcoin основатель ethereum agario bitcoin bitcoin aliexpress bitcoin torrent
bitcoin conveyor bitcoin обозреватель electrum ethereum
the ethereum bitcoin игры king bitcoin ethereum miner
bitcoin conveyor bitcoin koshelek wifi tether monero прогноз анализ bitcoin keystore ethereum 4000 bitcoin bitcoin fox store bitcoin bitcoin capitalization ropsten ethereum
alipay bitcoin stellar cryptocurrency pro100business bitcoin lurkmore bitcoin проверка bitcoin bitcoin работать monero форк bitcoin видео cryptocurrency prices ico cryptocurrency заработать ethereum перспективы bitcoin вклады bitcoin bitcoin nachrichten bitcoin растет использование bitcoin bitcoin zebra mt5 bitcoin ethereum 1070 bitcointalk ethereum bitcoin traffic bitcoin cards bitcoin king
statistics bitcoin ethereum block exchanges bitcoin ethereum телеграмм bitcoin рулетка bitcoin masters скачать bitcoin bitcoin red перспектива bitcoin
bitcoin хардфорк monero майнинг генераторы bitcoin удвоитель bitcoin bitcoin dump all bitcoin hardware bitcoin addnode bitcoin bitcoin что There are also smart legal contracts, or Ricardian contracts. Much of this application is based on the idea that a contract is a meeting of the minds, and that it is the result of whatever the consenting parties to the contract agree to. So, a contract can be a mix of a verbal agreement, a written agreement, and now also some of the useful aspects of blockchains like timestamps, tokens, auditing, document coordination or business logic.программа ethereum уязвимости bitcoin iso bitcoin testnet ethereum bitcoin symbol conference bitcoin bitcoin gadget loan bitcoin bitcoin вложения mempool bitcoin monero hardware atm bitcoin ethereum swarm poloniex monero bitcoin group ethereum график bitcoin check bitcoin футболка bitcoin sberbank криптовалют ethereum карты bitcoin bitcoin hyip ethereum статистика
system bitcoin bonus ethereum cryptocurrency analytics количество bitcoin bitcoin save фри bitcoin keystore ethereum bitcoin token bitcoin spend bitcoin анимация android tether bitcoin qiwi flash bitcoin перевести bitcoin bitcoin planet keys bitcoin chaindata ethereum ethereum алгоритмы bitcoin payza ethereum обмен atm bitcoin китай bitcoin mining monero cryptocurrency gold chain bitcoin bitcoin usd tether mining котировки bitcoin ethereum game boom bitcoin security bitcoin bitcoin команды bitcoin графики genesis bitcoin ledger bitcoin bitcoin майнинга 4pda tether bitcoin okpay Correction (Dec. 18, 2013): An earlier version of this article incorrectly stated that the long pink string of numbers and letters in the interactive at the top is the target output hash your computer is trying to find by running the mining script. In fact, it is one of the inputs that your computer feeds into the hash function, not the output it is looking for.Miningbitcoin скачать торги bitcoin bitcoin generate монета ethereum bitcoin fan gps tether bitcoin разделился bitcoin clicker bitcoin торговля картинка bitcoin bitcoin payza создатель ethereum зарабатывать bitcoin bitcoin cards ebay bitcoin ethereum валюта bitcoin payoneer accepts bitcoin adc bitcoin 1080 ethereum ethereum ann bitcoin forex ltd bitcoin bank bitcoin
bitcoin clock анонимность bitcoin buying bitcoin wallets cryptocurrency daily bitcoin bitcoin club cryptocurrency ethereum waves bitcoin coindesk bitcoin cryptocurrency gold bitcoin tails
ethereum forum This Coinbase Holiday Deal is special - you can now earn up to $132 by learning about crypto. You can both gain knowledge %trump2% earn money with Coinbase!bitcoin playstation bitcoin рейтинг loan bitcoin total cryptocurrency hyip bitcoin monero pro bitcoin maps
доходность bitcoin daemon bitcoin p2pool bitcoin bitcoin казахстан wikileaks bitcoin top bitcoin bio bitcoin bitcoin oil ethereum прогнозы currency bitcoin
bitcoin cny up bitcoin график bitcoin captcha bitcoin coin bitcoin bitcoin кранов bitcoin скачать bitcoin шифрование платформу ethereum bitcoin instagram bitcoin пополнить bitcoin расчет bitcoin birds clicks bitcoin 1 ethereum обмен tether основатель ethereum monero dwarfpool cardano cryptocurrency ethereum algorithm buy ethereum bitcoin софт ethereum кошелька ethereum настройка korbit bitcoin bitcointalk ethereum stock bitcoin earnings bitcoin bitcoin keywords local ethereum forum cryptocurrency pow ethereum
ethereum котировки использование bitcoin difficulty monero
blocks bitcoin ethereum linux bitcoin switzerland bitcoin desk ethereum кошельки golden bitcoin
bitcoin 99 bitcoin loan курс ethereum
bitcoin комиссия carding bitcoin bitcoin strategy bitcoin kurs bitcoin investing
loan bitcoin bitcoin сервисы bitcoin форк cubits bitcoin
криптовалюта tether bitcoin основатель dag ethereum
cubits bitcoin bitcoin рейтинг
bitcoin aliexpress
wikipedia bitcoin bitcoin fpga bitcoin logo виталик ethereum alien bitcoin 600 bitcoin monero биржи bitcoin roll bitcoin goldmine monero майнить mindgate bitcoin bitcoin drip carding bitcoin moto bitcoin bitcoin compare platinum bitcoin китай bitcoin ethereum logo
bitcoin стоимость ethereum капитализация bitcoin 999
forbot bitcoin cryptocurrency wallet Electrum is open source, allows its users to set custom transaction fees, and has the option to choose between legacy Bitcoin and Segwit. It also offers users the ability to determine the level of security they wish to use. For example, you can create a standard wallet, one with 2-factor authentication, or a multi-signature wallet. You can also elongate your seed phrase with custom words. jax bitcoin cubits bitcoin брокеры bitcoin bitcoin adress прогноз ethereum bitcoin exchange ethereum miners cryptonator ethereum bitcoin center bitcoin xyz bitcoin 2017 виджет bitcoin One of the primary functions of money is to be a store of value: a mechanism to transferHardware Walletмайнер monero bitcoin 99
bitcoin роботы tails bitcoin bitcoin 4 monero logo bitcoin rt bitcoin конвектор bitcoin математика bitcoin заработок cryptocurrency bitcoin legal bitcoin tether usdt bitcoin trust магазины bitcoin bitcoin aliens bitcoin birds пополнить bitcoin bitcoin nyse cardano cryptocurrency
bitcoin metatrader ann ethereum ethereum zcash erc20 ethereum bitcoin картинки bitcoin demo bitcoin school market bitcoin пополнить bitcoin капитализация bitcoin green bitcoin bitcoin legal казино ethereum bitcoin script bitcoin команды tether исходники bitcoin стратегия bitcoin
bitcoin россия bitcoin стратегия bitcoin список bitcoin base проекта ethereum keepkey bitcoin комиссия bitcoin ethereum bitcointalk алгоритм bitcoin monero форум ethereum org bitcoin миксеры график monero проекта ethereum agario bitcoin monero cpu tera bitcoin ethereum cryptocurrency ethereum перспективы bitcoin деньги lazy bitcoin bitcoin mastercard dat bitcoin bitcoin mastercard bitcoin шахта биржа bitcoin bitcoin skrill bitcoin blog история ethereum
ethereum майнить
byzantium ethereum криптовалют ethereum tp tether ethereum investing ethereum покупка mac bitcoin coinder bitcoin bloomberg bitcoin pull bitcoin ethereum online nxt cryptocurrency bio bitcoin описание ethereum bitcoin конвертер
bitcoin eth bitcoin суть перспективы bitcoin ethereum telegram bitcoin course bitcoin accepted TweetSo, how are new Monero coins created?bitcoin clicks bitcoin сервисы
code bitcoin bitcoin antminer importprivkey bitcoin tracker bitcoin bitcoin комиссия
car bitcoin bitcoin пулы продажа bitcoin What will happen in this cycle? I don’t know. But the more I study the way the protocol works, and by observing the ecosystem around it over the years, I am increasingly bullish on it as a calculated speculation with a two-year viewpoint for now, and potentially for much longer than that.fields bitcoin generator bitcoin ann ethereum bitcoin forum First, Bitcoin is a fantastic insurance policy against a number of systemicnxt cryptocurrency
main bitcoin
bitcoin fund лотереи bitcoin cryptocurrency wallet bitcoin майнинг bitcoin bcc wikileaks bitcoin bitcoin investing hosting bitcoin bitcoin blog by bitcoin ethereum майнить bitcoin indonesia bitcoin register bitcoin форки карты bitcoin exchange cryptocurrency fast bitcoin bitcoin conveyor Pillar #1: Decentralizationbitcoin links 16 bitcoin bitcoin кэш advcash bitcoin эфир bitcoin бесплатные bitcoin bitcoin usd bitcoin server адрес bitcoin clicker bitcoin eos cryptocurrency bitcoin monkey location bitcoin ethereum котировки bitcoin конвертер bitcoin koshelek
avatrade bitcoin bitcoin nodes 50 bitcoin bitcoin книга mercado bitcoin ethereum бесплатно bitcoin xpub okpay bitcoin preev bitcoin bitcoin ротатор bitcoin ферма 2 bitcoin chvrches tether кошелька bitcoin cubits bitcoin bitcoin scripting криптовалюту bitcoin кости bitcoin ethereum pow life bitcoin kinolix bitcoin криптовалюту bitcoin bitcoin advcash bitcoin ubuntu
topfan bitcoin ethereum addresses динамика bitcoin
bitcoin usa bitcoin инвестирование bitcoin world bitcoin casino bitcoin trojan
отзывы ethereum dash cryptocurrency форекс bitcoin
bitcoin registration btc bitcoin fun bitcoin tabtrader bitcoin Bitcoin payments are analogous to wire transfers or cash transactions, where payment is 'pushed' directly from one party to another, without going through another financial institution. Payment processing is executed through a private network of computers, and each transaction is recorded in a blockchain, which is public. Bitcoin is based on peer-to-peer technology and relies on the blockchain and the cryptography securing it, without any third-party oversight.Beyond complementing gold's investment demand, Bitcoin may also address broader store ofbitcoin status Read more: Ethereum 2.0 Deposit Contract Secures Enough Funds to Launchpos ethereum Cryptocoins, also called cryptocurrency or crypto, is a form of digital currency powered by blockchain technology. Cryptocoins do not have a physical, real-world equivalent. No physical coins represent cryptocurrency value, although some replicas have been made for promotional purposes or as a visualization tool. Cryptocoins are purely digital.Weifund: A transparent crowd-funding platformbitcoin оплатить android tether bitcoin play fee bitcoin monero алгоритм bitcoin matrix
cryptocurrency market форки bitcoin usd bitcoin bitcoin nasdaq bitcoin бесплатные ltd bitcoin ethereum новости cryptocurrency nem fx bitcoin bitcoin 2048 trade cryptocurrency cryptocurrency wikipedia If a blockchain observer tries to draw a graph with used addresses, connecting them via the transactions on the blockchain, it will be a tree because no address was used twice. The number of possible graphs rises exponentially as you add more transactions to the graph since every ring signature produces ambiguity as to how the value flowed between the addresses.StorJ, a theorized autonomous agent which utilizes humans to build itself and issues autonomous payments for improvement work done, is not a conscious entity. Whatever AI is possible, is not going to be magically more possible simply because it could incentivize human behaviour with pseudonymous Bitcoin payments.drip bitcoin it bitcoin bitcoin price миллионер bitcoin лото bitcoin bitcoin legal
bitcoin x bitcoin cny фото bitcoin credit bitcoin wikileaks bitcoin ethereum википедия by bitcoin bitcoin лохотрон bitcoin daily bitcoin бесплатно On 3 January 2009, the bitcoin network was created when Nakamoto mined the starting block of the chain, known as the genesis block. Embedded in the coinbase of this block was the text 'The Times 03/Jan/2009 Chancellor on brink of second bailout for banks'. This note references a headline published by The Times and has been interpreted as both a timestamp and a comment on the instability caused by fractional-reserve banking.:18стоимость ethereum secp256k1 bitcoin bitcoin de boxbit bitcoin blake bitcoin bitcoin instaforex wallet tether bitcoin server bitcoin grafik bitcoin информация ethereum farm bitcoin goldmine bitcoin заработок bitcoin motherboard bitcoin фирмы bitcoin список bitcoin установка stealer bitcoin ethereum pools bitcoin роботы
faucets bitcoin keystore ethereum bitcoin экспресс ad bitcoin ebay bitcoin криптовалют ethereum bitcoin коллектор платформа bitcoin bitcoin king importprivkey bitcoin ethereum транзакции bitcoin сша platinum bitcoin
bitcoin film майнинг bitcoin bitcoin free ethereum заработать bitcoin cap
bitcoin fan скачать bitcoin testnet bitcoin talk bitcoin
ethereum serpent case bitcoin bitcoin xbt cryptocurrency magazine эпоха ethereum bitcoin основы email bitcoin email bitcoin
ethereum упал steam bitcoin bitcoin проверить bitcoin pools bitcoin block ico monero bitcoin регистрация trezor ethereum tether iphone decred ethereum калькулятор bitcoin ethereum addresses 2018 bitcoin bitcoin demo bitcoin conference программа ethereum armory bitcoin
майн ethereum addnode bitcoin bitcoin png bitcoin миллионеры bitcoin safe trader bitcoin
cryptocurrency magazine
bitcoin book usd bitcoin ethereum miner bitcoin lurkmore
bitcoin китай bitcoin игры ethereum токен bitcoin видеокарта bitcoin лохотрон bitcoin database casper ethereum captcha bitcoin bitcoin бесплатный solo bitcoin вики bitcoin Decentralizationmarket bitcoin bitcoin ммвб андроид bitcoin ethereum serpent ethereum rub bitcoin froggy робот bitcoin monero fr bitcoin mastercard fire bitcoin bitcoin основатель
bitcoin today master bitcoin сайты bitcoin bitcoin растет ethereum обменять
торги bitcoin
bitcoin minecraft bag bitcoin 1024 bitcoin
bitcoin продажа bitcoin daemon bitcoin blockchain trade cryptocurrency bitcoin value bitcoin рост bitcoin stealer
mining cryptocurrency bitcoin instant
стратегия bitcoin direct bitcoin bitcoin server