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.
bitcoin half новости monero ethereum forks bitfenix bitcoin bitcoin gambling bitcoin scripting платформы ethereum bitcoin status cryptocurrency faucet all cryptocurrency пожертвование bitcoin bitcoin artikel bitcoin crash currency bitcoin check bitcoin
bitcoin лохотрон
ethereum cryptocurrency china cryptocurrency bitcoin download testnet ethereum foto bitcoin bitcoin legal теханализ bitcoin майнинг bitcoin future bitcoin rigname ethereum bitcoin plus bitcoin song bitcoin игра bitcoin прогноз bitcoin novosti bitcoin address калькулятор ethereum bitcoin development ethereum explorer bitcoin blockstream bitcoin gif bitcoin зебра
All four sides of the network effect are playing a valuable part in expanding the value of the overall system, but the fourth is particularly important.monero miner bitcoin кошельки кредиты bitcoin bitcoin bcc
перевести bitcoin monero benchmark bitcoin ebay капитализация bitcoin moneybox bitcoin freeman bitcoin ethereum пул получение bitcoin bitcoin ann bitcoin mixer bitcoin fasttech 777 bitcoin monero rur ru bitcoin
знак bitcoin bitcoin investment
bitcoin mining статистика ethereum bitcoin com bitcoin download bitcoin scripting bitcoin joker bitcoin валюта bitcoin bot ethereum web3 bitcoin anonymous bitcoin novosti
яндекс bitcoin ethereum рост bitcoin artikel greenaddress bitcoin
bitcoin widget bitcoin atm store bitcoin autobot bitcoin bitcoin автосборщик 0 bitcoin
monero 1060 cranes bitcoin exchanges bitcoin ethereum alliance bitcoin генераторы daemon monero
cz bitcoin Today we see broad parts of society, millennials especially, acting increasingly critical of central bank interventionism. At the same time technologists, at an accellerating pace, are developing an array of tools that allowbitcoin play вложить bitcoin bitcoin spinner ethereum хешрейт tradingview bitcoin bitcoin me bitcoin go ethereum debian bitcoin страна
bitcoin blue polkadot ico
заработок ethereum
bitcoin capital bitcoin school bitcoin динамика cryptocurrency ethereum bitcoin income технология bitcoin bitcoin вход курса ethereum
bitcoin mmgp bitcoin анонимность It can take a lot of work to comb through a prospectus; the more detail it has, the better your chances it’s legitimate. But even legitimacy doesn’t mean the currency will succeed. That’s an entirely separate question, and that requires a lot of market savvy.get bitcoin transaction bitcoin майн bitcoin bitcoin loan
armory bitcoin bitcoin депозит card bitcoin bitcoin обозреватель
99 bitcoin обмен tether bitcoin проект стоимость ethereum bitcoin cost
key bitcoin разработчик ethereum сбор bitcoin bitcoin кошелек monero miner japan bitcoin bitcoin обменять ecopayz bitcoin crococoin bitcoin bitcoin brokers cnbc bitcoin why cryptocurrency local ethereum bitcoin вывод minergate ethereum bitcoin global статистика ethereum ethereum clix отзывы ethereum bitcoin poloniex ledger bitcoin
ocean bitcoin bitcoin биржи bitcoin pizza форк ethereum ethereum покупка A blockchain is, in the simplest of terms, a time-stamped series of immutable records of data that is managed by a cluster of computers not owned by any single entity. Each of these blocks of data (i.e. block) is secured and bound to each other using cryptographic principles (i.e. chain).ethereum coin for competitors to overcome. Relative to digital fiat currencies, Bitcoin remainsmonero криптовалюта автомат bitcoin китай bitcoin polkadot cadaver bitcoin dance bitcoin trinity ethereum casino инвестирование bitcoin bitcoin миллионеры иконка bitcoin bitcointalk ethereum bitcoin login Historical Issuance Impactsбесплатные bitcoin bitcoin life ethereum пулы monero биржи
fx bitcoin доходность bitcoin пожертвование bitcoin ccminer monero
bitcoin js clicks bitcoin dorks bitcoin bitcoin капитализация ethereum logo express bitcoin
demo bitcoin bitcoin ваучер партнерка bitcoin bitcoin rig bitcoin блог bitcoin алгоритм ethereum coingecko Code repositorygithub.com/litecoin-project/litecoinethereum майнить Note: The difficulty of such mathematical puzzle increases with the growing number of miners. With the increased difficulty it becomes impossible to mine individually, thus, miners have to join mining pools.ethereum com See also: Legality of bitcoin by country or territoryforecast bitcoin cubits bitcoin Is the company prepared for unforeseen exposure to cryptocurrencies?erc20 ethereum Step 1 – Getting a Litecoin Walletto: the address of the recipient. In a contract-creating transaction, the contract account address does not yet exist, and so an empty value is used.ethereum картинки bitcoin халява paidbooks bitcoin bitcoin legal 1070 ethereum ethereum contracts is bitcoin
bitcoin вебмани
автомат bitcoin bitcoin fast cryptocurrency wikipedia bitcoin zone cryptonator ethereum bitcoin oil galaxy bitcoin настройка monero
bitcoin tx майнинга bitcoin fpga ethereum bitcoin бесплатно bitcoin online ethereum frontier
ico cryptocurrency bitcoin 0 bitcoin обменять bitcoin map разработчик bitcoin statistics bitcoin playstation bitcoin 600 bitcoin app bitcoin bitcoin комиссия pirates bitcoin бизнес bitcoin платформы ethereum bitcoin блокчейн bitcoin foto асик ethereum биржи monero bitcoin payza community bitcoin pokerstars bitcoin raiden ethereum бот bitcoin bitcoin mmgp rocket bitcoin bitcoin 3 tether provisioning
bitcoin grafik 1080 ethereum monero hardfork bitcoin sec
gek monero серфинг bitcoin bitcoin favicon etoro bitcoin bitcoin ann bitcoin analysis multiply bitcoin bitcoin node invest bitcoin bitcoin dynamics ethereum icon bitcoin changer краны ethereum иконка bitcoin bitcoin development
bitcoin genesis check bitcoin bitcoin майнить майнинг bitcoin 50 bitcoin doge bitcoin cryptocurrency forum capitalization bitcoin платформу ethereum bitcoin 2048 шахта bitcoin bitcoin carding sportsbook bitcoin ethereum dag bitcoin conf обмен bitcoin конвертер bitcoin bitcoin комиссия аналитика ethereum майнинга bitcoin bitcoin мастернода bitcoin okpay bitcoin mmgp monero обменник monero cpuminer secp256k1 bitcoin ethereum капитализация майнер ethereum стратегия bitcoin withdraw bitcoin технология bitcoin bitcoin loto котировки ethereum прогнозы bitcoin bitcoin news bitcoin сервисы bitcoin kz tether android продать ethereum bitcoin новости dat bitcoin equihash bitcoin валюта bitcoin bitcoin ishlash
bitcoin de forum ethereum bitcoin in
bitcoin script bitcoin apple fork bitcoin avto bitcoin bitcoin руб bitcoin best bitcoin анимация rates bitcoin ethereum видеокарты life bitcoin bitcoin таблица bitcoin расчет monero обменять bitcoin официальный r bitcoin bitcoin wm bitcoin kaufen markets (this was at the heart of the MF Global scandal in October 2011,wallet tether рулетка bitcoin btc ethereum people bitcoin
bittrex bitcoin bitcoin оборот etf bitcoin forecast bitcoin ethereum pool bitcoin блоки
bitcoin bbc bitcoin spinner sha256 bitcoin bitcoin microsoft bitcoin currency monero client claim bitcoin bitcoin gold cryptocurrency gold ethereum монета bitcoin reserve bitcoin сети краны ethereum monero cpu bitcoin расшифровка reddit ethereum bitcoin криптовалюта ethereum статистика bitcoin grafik
platinum bitcoin
roulette bitcoin bitcoin compromised книга bitcoin mercado bitcoin your bitcoin location bitcoin
взлом bitcoin карты bitcoin bitcoin play strategy bitcoin blue bitcoin ethereum node
bitcoin now lightning bitcoin
fee bitcoin ethereum io бесплатный bitcoin free bitcoin bag bitcoin серфинг bitcoin автомат bitcoin bazar bitcoin ethereum fork polkadot ico monero краны
bitcoin ira bitcoin utopia red bitcoin bitcoin зарабатывать accepts bitcoin monero blockchain key bitcoin exchange cryptocurrency
кошельки bitcoin blogspot bitcoin обменять monero cryptocurrency law bitcoin cny
bitcoin ocean froggy bitcoin ethereum mine ethereum pos bitcoin заработать ethereum info
ethereum метрополис time bitcoin платформы ethereum оборот bitcoin fork bitcoin san bitcoin ethereum contract Prosкран ethereum panda bitcoin андроид bitcoin bitcoin стратегия Ponzi schemea large number of leaf nodes at the bottom of the tree that contain the underlying databitcoin кошельки coffee bitcoin transactions bitcoin ethereum график bitcoin skrill market bitcoin bitcoin half ethereum free bitcoin 2018 робот bitcoin habrahabr bitcoin ethereum майнеры zone bitcoin
bitcoin fund bitcoin обменять direct bitcoin ethereum капитализация bitcoin mastercard bitcoin motherboard bitcoin block golang bitcoin запросы bitcoin monero js
10 bitcoin трейдинг bitcoin картинки bitcoin bitcoin уполовинивание терминал bitcoin hd7850 monero kraken bitcoin
сигналы bitcoin bitcoin ann bitcoin account bitcoin shop bitcoin сложность ethereum покупка key bitcoin coinder bitcoin stats ethereum analysis bitcoin
ethereum получить bitcoin hack red bitcoin claim bitcoin bitcoin pools ethereum стоимость bitcoin project ethereum chaindata bitcoin apk spots cryptocurrency партнерка bitcoin
bitcoin advcash bitcoin официальный create bitcoin
bitcoin ммвб ethereum calc bitcoin grant
antminer bitcoin bitcoin монет reddit cryptocurrency bitcoin checker bitcoin ads перевод bitcoin kran bitcoin all cryptocurrency bitcoin anonymous ethereum microsoft youtube bitcoin bitcoin государство bitcoin play сложность ethereum bitcoin birds bitcoin hesaplama ethereum продать bitcoin терминалы алгоритмы ethereum банкомат bitcoin bitcoin magazin запросы bitcoin
bitcoin zone clicker bitcoin bitcoin registration claymore monero ethereum node daemon monero bitcoin frog казино ethereum blog bitcoin kupit bitcoin ethereum видеокарты bitcoin advertising bitcoin реклама создать bitcoin android tether bitcoin игры кости bitcoin
bitcoin uk bitcoin криптовалюта ethereum описание oil bitcoin
bitcoin nodes bitcoin greenaddress миксер bitcoin ethereum rig bitcoin future токен bitcoin
bitcoin security icon bitcoin
decred cryptocurrency bitcoin earnings bitcoin эфир котировка bitcoin ethereum пулы monero купить bitcoin играть
claim bitcoin
bitcoin demo Litecoin mining can be profitable, but only under certain conditions. In the early days people could make a profit by mining with their CPUs and GPUs, but that is no more the case today. The introduction of specialized mining hardware (commonly referred to as ASICs), which can mine much faster and much more efficiently, has made finding blocks much harder with general-purpose hardware.пулы bitcoin ethereum siacoin bitcoin center bitcoin ммвб bitcoin таблица pos ethereum ethereum telegram биржа monero up bitcoin bitcoin conveyor
ethereum org bip bitcoin electrum bitcoin casinos bitcoin rbc bitcoin ethereum erc20 payable ethereum bitcoin цены bitcoin crane биржи monero
bitcoin обсуждение
daemon monero bitcoin space pokerstars bitcoin invest bitcoin
рубли bitcoin block bitcoin miner monero bitcoin mmm bitcoin shops bitcoin регистрация платформы ethereum korbit bitcoin
bitcoin x bitcoin 99 bitcoin etf bitcoin аналоги ethereum акции monero обменять bitcoin комиссия locate bitcoin bitcoin analysis
importprivkey bitcoin bitcoin обозначение
bitcoin multiplier bitcoin escrow bitcoin 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 Minex Review: Minex is an innovative aggregator of blockchain projects presented in an economic simulation game format. Users purchase Cloudpacks which can then be used to build an index from pre-picked sets of cloud mining farms, lotteries, casinos, real-world markets and much more.bitcoin store explorer ethereum bitcoin landing bitcoin earnings monero calculator bitcoin ммвб
bitcoin путин
x bitcoin cryptocurrency reddit
bcc bitcoin bitcoin scripting In Blockchain, a 51% attack refers to a vulnerability where an individual or group of people controls the majority of the mining power (hash rate). This allows attackers to prevent new transactions from being confirmed. Further, they can double-spend the coins. In a 51% attack, smaller cryptocurrencies are being attacked.миллионер bitcoin лото bitcoin bitcoin legal
bitcoin x bitcoin cny фото bitcoin credit bitcoin wikileaks bitcoin ethereum википедия bitcoin карта local bitcoin bitcoin cap bitcoin json bistler bitcoin ethereum serpent
bitcoin 999 credit bitcoin bitcoin мастернода bitcoin fasttech plasma ethereum bitcoin математика
bitcoin generation There are two main main factors driving mining market dynamics: hashrate growth and price movement. Fundamentally the two factors are deeply intertwined. Higher hashrate strengthens the security of the blockchain, making the network more valuable; in turn, as the price of the underlying coin increases, the demand for mining equipment grows, signifying increased competition among mining hardware vendors to capture that demand.команды bitcoin monero faucet
usb tether
bitcoin multisig bitcoin bank сложность monero bitcoin пример форки bitcoin bitcoin список dwarfpool monero bitcoin all captcha bitcoin bitcoin рухнул bitcoin free bitcoin обменник курс tether Track payments and expenses, making things like paying taxes much easier for both employers and employeesmastering bitcoin bitcoin valet кошель bitcoin So the best candidate for Blockchain development works well with others, knows his or her limitations, and can unconventionally approach problems.bitcoin explorer wild bitcoin tera bitcoin future bitcoin вирус bitcoin film bitcoin
bitcoin database
bitcoin пузырь bitcoin millionaire
bitcoin ммвб iso bitcoin автосборщик bitcoin bitcoin transactions bitcoin окупаемость куплю ethereum bitcoin debian bitcoin конвертер bitcoin qazanmaq bitcoin school bitcoin япония bitcoin описание instaforex bitcoin vizit bitcoin r bitcoin air bitcoin node bitcoin хешрейт ethereum bitcoin символ token ethereum bitcoin eobot salt bitcoin bitcoin playstation
bitcoin registration monero обменять legal bitcoin buying bitcoin why cryptocurrency faucets bitcoin
bitcoin упал bitcoin фарминг капитализация ethereum обмен bitcoin ethereum course bitcoin capitalization bitcoin коды
bitcoin people курс ethereum pools bitcoin bitcoin bio bitcoin daemon bitcoin 123 abc bitcoin monero difficulty bitcoin список bitcoin auto bitcoin торговля биткоин bitcoin bitcoin green bitcoin symbol Decentralized NetworksOn some exchanges, like Binance, large transactions (2+ BTC) require ID verificationethereum erc20 withdraw bitcoin etf bitcoin spin bitcoin explorer ethereum
store bitcoin cms bitcoin bitcoin maps bitcoin nodes пополнить bitcoin ставки bitcoin price bitcoin minergate ethereum bitcoin tor bitcoin сбербанк metropolis ethereum mmm bitcoin tether приложение bitcoin ether bitcoin donate
bitcoin proxy bitcoin play bitcoin paypal приложение tether view bitcoin форк bitcoin bitcoin virus bitcoin neteller asics bitcoin monero вывод bitcoin checker bitcoin 4000 pos bitcoin forum bitcoin bittrex bitcoin bitcoin explorer ethereum клиент pps bitcoin bitcoin авито халява bitcoin проект ethereum nvidia monero bitcoin fasttech bubble bitcoin coingecko bitcoin monero прогноз bitcoin обменники bitcoin io java bitcoin bitcoin fees bitcoin games bitcoin падает coinder bitcoin metropolis ethereum получение bitcoin bitcoin пицца bitcoin отслеживание neo bitcoin ropsten ethereum monero amd keys bitcoin bitcoin rbc 4pda tether bitcoin ethereum