Basic Concepts
Currency
Alice wants to buy the Alpaca socks which Bob has for sale. In return, she must provide something of equal value to Bob. The most efficient way to do this is by using a medium of exchange that Bob accepts which would be classified as currency. Currency makes trade easier by eliminating the need for coincidence of wants required in other systems of trade such as barter. Currency adoption and acceptance can be global, national, or in some cases local or community-based.
Banks
Alice need not provide currency to Bob in-person. She may instead transfer this value by first entrusting her currency to a bank who promises to store and protect Alice's currency notes. The bank gives Alice a written promise (called a "bank statement") that entitles her to withdraw the same number of currency bills that she deposited. Since the money is still Alice's, she is entitled to do with it whatever she pleases, and the bank (like most banks), for a small fee, will do Alice the service of passing on the currency bills to Bob on her behalf. This is done by Alice's bank by giving the dollar bills to Bob's bank and informing them that the money is for Bob, who will then see the amount the next time he checks his balance or receives his bank statement.
Since banks have many customers, and bank employees require money for doing the job of talking to people and signing documents, banks in recent times have been using machines such as ATMs and web servers that do the job of interacting with customers instead of paid bank employees. The task of these machines is to learn what each customer wants to do with their money and, to the extent that it is possible, act on what the customer wants (for example, ATMs can hand out cash). Customers can always know how much money they have in their accounts, and they are confident that the numbers they see in their bank statements and on their computer screens accurately reflect the number of dollars that they can get from the bank on demand. They can be so sure of this that they can accept those numbers in the same way they accept paper banknotes (this is similar to the way people started accepting paper dollars when they had been accepting gold or silver).
Such a system has several disadvantages:
It is costly. EFTs in Europe can cost 25 euros. Credit transactions can cost several percent of the transaction.
It is slow. Checking and low cost wire services take days to complete.
In most cases, it cannot be anonymous.
Accounts can be frozen, or their balance partially or wholly confiscated.
Banks and other payment processors like PayPal, Visa, and Mastercard may refuse to process payments for certain legal entities.
Bitcoin is a system of owning and voluntarily transferring amounts of so-called bitcoins, in a manner similar to an on-line banking, but pseudonymously and without reliance on a central authority to maintain account balances. If bitcoins are valuable, it is because they are useful and limited in supply.
Bitcoin Basics
Creation of coins
The creation of coins must be limited for the currency to have any value.
New coins are slowly mined into existence by following a mutually agreed-upon set of rules. A user mining bitcoins is running a software program that searches for a solution to a very difficult math problem the difficulty of which is precisely known. This difficulty is automatically adjusted on a predictable schedule so that the number of solutions found globally for a given unit of time is constant: the global system aims for 6 per hour. When a solution is found, the user may tell everyone of the existence of this newly found solution along with other information packaged together in what is called a "block". The solution itself is a proof-of-work or PoW. It is hard to find, but easy to verify.
Blocks create 12.5 new bitcoins at present [October 2016]. This amount, known as the block reward, is an incentive for people to perform the computation work required for generating blocks. Roughly every 4 years, the number of bitcoins that can be "mined" in a block reduces by 50%. Originally the block reward was 50 bitcoins; it halved in November 2012; it then halved again in July 2016. Any block that is created by a malicious user that does not follow this rule (or any other rules) will be rejected by everyone else. In the end, no more than 21 million bitcoins will ever exist.
Because the block reward will decrease over the long term, miners will some day instead pay for their hardware and electricity costs by collecting transaction fees. The sender of money may voluntarily pay a small transaction fee which will be kept by whoever finds the next block. Paying this fee will encourage miners to include the transaction in a block more quickly.
Sending payments
To guarantee that a third-party, let's call her Eve, cannot spend other people's bitcoins by creating transactions in their names, Bitcoin uses public key cryptography to make and verify digital signatures. In this system, each person, such as Alice or Bob, has one or more addresses each with an associated pair of public and private keys that they may hold in a wallet. Only the user with the private key can sign a transaction to give some of their bitcoins to somebody else, but anyone can validate the signature using that user’s public key.
Suppose Alice wants to send a bitcoin to Bob.
Bob sends his address to Alice.
Alice adds Bob’s address and the amount of bitcoins to transfer to a message: a 'transaction' message.
Alice signs the transaction with her private key, and announces her public key for signature verification.
Alice broadcasts the transaction on the Bitcoin network for all to see.
(Only the first two steps require human action. The rest is done by the Bitcoin client software.)
Looking at this transaction from the outside, anyone who knows that these addresses belong to Alice and Bob can see that Alice has agreed to transfer the amount to Bob, because nobody else has Alice's private key. Alice would be foolish to give her private key to other people, as this would allow them to sign transactions in her name, removing funds from her control.
Later on, when Bob wishes to transfer the same bitcoins to Charley, he will do the same thing:
Charlie sends Bob his address.
Bob adds Charlie's address and the amount of bitcoins to transfer to a message: a 'transaction' message.
Bob signs the transaction with his private key, and announces his public key for signature verification.
Bob broadcasts the transaction on the Bitcoin network for all to see.
Only Bob can do this because only he has the private key that can create a valid signature for the transaction.
Eve cannot change whose coins these are by replacing Bob’s address with her address, because Alice signed the transfer to Bob using her own private key, which is kept secret from Eve, and instructing that the coins which were hers now belong to Bob. So, if Charlie accepts that the original coin was in the hands of Alice, he will also accept the fact that this coin was later passed to Bob, and now Bob is passing this same coin to him.
Preventing double-spending
The process described above does not prevent Alice from using the same bitcoins in more than one transaction. The following process does; this is the primary innovation behind Bitcoin.
Details about the transaction are sent and forwarded to all or as many other computers as possible.
A constantly growing chain of blocks that contains a record of all transactions is collectively maintained by all computers (each has a full copy).
To be accepted in the chain, transaction blocks must be valid and must include proof of work (one block generated by the network every 10 minutes).
Blocks are chained in a way so that, if any one is modified, all following blocks will have to be recomputed.
When multiple valid continuations to this chain appear, only the longest such branch is accepted and it is then extended further.
When Bob sees that his transaction has been included in a block, which has been made part of the single longest and fastest-growing block chain (extended with significant computational effort), he can be confident that the transaction by Alice has been accepted by the computers in the network and is permanently recorded, preventing Alice from creating a second transaction with the same coin. In order for Alice to thwart this system and double-spend her coins, she would need to muster more computing power than all other Bitcoin users combined.
Anonymity
When it comes to the Bitcoin network itself, there are no "accounts" to set up, and no e-mail addresses, user-names or passwords are required to hold or spend bitcoins. Each balance is simply associated with an address and its public-private key pair. The money "belongs" to anyone who has the private key and can sign transactions with it. Moreover, those keys do not have to be registered anywhere in advance, as they are only used when required for a transaction. Transacting parties do not need to know each other's identity in the same way that a store owner does not know a cash-paying customer's name.
A Bitcoin address mathematically corresponds to a public key and looks like this:
1PHYrmdJ22MKbJevpb3MBNpVckjZHt89hz
Each person can have many such addresses, each with its own balance, which makes it very difficult to know which person owns what amount. In order to protect his privacy, Bob can generate a new public-private key pair for each individual receiving transaction and the Bitcoin software encourages this behavior by default. Continuing the example from above, when Charlie receives the bitcoins from Bob, Charlie will not be able to identify who owned the bitcoins before Bob.
Capitalization / Nomenclature
Since Bitcoin is both a currency and a protocol, capitalization can be confusing. Accepted practice is to use Bitcoin (singular with an upper case letter B) to label the protocol, software, and community, and bitcoins (with a lower case b) to label units of the currency.
Where to see and explore
You can directly explore the system in action by visiting BTC.com, Biteasy.com, Blockchain.info, Blokr.io Bitcoin Block Explorer or Bitcoin Block Explorer. The site shows you the latest blocks in the block chain. The block chain contains the agreed history of all transactions that took place in the system. Note how many blocks were generated in the last hour, which on average will be 6. Also notice the number of transactions and the total amount transferred in the last hour (last time I checked it was about 64 and 15K). This should give you an indication of how active the system is.
Next, navigate to one of these blocks. The block's hash begins with a run of zeros. This is what made creating the block so difficult; a hash that begins with many zeros is much more difficult to find than a hash with few or no zeros. The computer that generated this block had to try many Nonce values (also listed on the block's page) until it found one that generated this run of zeros. Next, see the line titled Previous block. Each block contains the hash of the block that came before it. This is what forms the chain of blocks. Now take a look at all the transactions the block contains. The first transaction is the income earned by the computer that generated this block. It includes a fixed amount of coins created out of "thin air" and possibly a fee collected from other transactions in the same block.
Drill down into any of the transactions and you will see how it is made up of one or more amounts coming in and out. Having more than one incoming and outgoing amount in a transaction enables the system to join and break amounts in any possible way, allowing for any fractional amount needed. Each incoming amount is a past transaction (which you can also view) from someone's address, and each outgoing amount is addressed to someone and will be part of a future transaction (which you can also navigate down into if it has already taken place.)
Finally, you can follow any of the addresses links and see what public information is available for them.
To get an impression of the amount of activity on the Bitcoin network, you might like to visit the monitoring websites Bitcoin Monitor and Bitcoin Watch. The first shows a real-time visualization of events on the Bitcoin network, and the second lists general statistics on the amount and size of recent transactions.
How many people use Bitcoin?
This is quite a difficult question to answer accurately. One approach is to count how many bitcoin clients connected to the network in the last 24 hours. We can do this because some clients transmit their addresses to the other members of the network periodically;
In September 2011, this method suggested that there were about 60,000 users.
In October 2014, according to Coindesk report there were more than 7.5 million bitcoin wallets.
In October 2016, according to blockchain.info user counts based on Blockchain wallet, there are about 8.8 mln registered Bitcoin users on its platform. Cointelegraph report
According to blockchain.info, from October 2016 till January 2018 the Bitcoin user base has almost tripled for total of 22 million users.
ethereum network bitcoin eth bitcoin torrent life bitcoin cryptocurrency wikipedia visa bitcoin bitcoin вирус платформа bitcoin
tabtrader bitcoin
bitcoin department счет bitcoin
bitcoin center bitcoin crypto
5 bitcoin bitcoin cards ethereum биткоин
bitcoin antminer ecdsa bitcoin wiki bitcoin
sell ethereum cryptocurrency calendar форки ethereum ethereum токены ethereum scan rx560 monero хардфорк monero
coffee bitcoin mixer bitcoin котировки ethereum bitcoin сатоши bitcoin auto bitcoin python bitcoin ixbt
bitcoin видеокарта bitcoin advcash bitcoin swiss курс ethereum cryptocurrency mining bitcoin серфинг bitcoin протокол биржа monero
bitcoin video transactions bitcoin спекуляция bitcoin ethereum получить price bitcoin валюта tether ethereum vk сервисы bitcoin математика bitcoin mining ethereum cryptocurrency faucet bitcoin вложения bitcoin майнить криптовалюты bitcoin bitcoin virus bitcoin ваучер monero майнинг mastering bitcoin
600 bitcoin hack bitcoin bitcoin ecdsa bitcoin client bitcoin сети bitcoin майнить fasterclick bitcoin
bitcoin x2
monero сложность bitcoin мерчант bitcoin faucets ethereum online loco bitcoin sec bitcoin bitcoin заработок bitcoin node monero калькулятор mining bitcoin сбор bitcoin добыча bitcoin bitcoin торговать monster bitcoin trading bitcoin дешевеет bitcoin bitcoin avalon 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.cryptocurrency market bitcoin click bitcoin mail bitcoin криптовалюта electrum bitcoin валюта bitcoin bitcoin express takara bitcoin connect bitcoin polkadot bitcoin валюты monero cpu bitcoin lite tcc bitcoin bitcoin приложение bitcoin alert cryptocurrency tech
bitcoin магазин
bitcoin talk ethereum rotator майнить monero ethereum прогнозы boom bitcoin The EVM is a Turing complete virtual machine, as defined earlier. The only limitation the EVM has that a typical Turing complete machine does not is that the EVM is intrinsically bound by gas. Thus, the total amount of computation that can be done is intrinsically limited by the amount of gas provided.monero pro bitcoin ledger my ethereum
bitcoin пример carding bitcoin bitcoin ключи криптовалюта monero cryptocurrency price смесители bitcoin difficulty bitcoin
monero майнер bitcoin matrix bitcoin symbol currency bitcoin е bitcoin gain bitcoin bitcoin tm bitcoin завести ethereum explorer tether транскрипция ethereum shares bitcoin code bitcoin joker erc20 ethereum
bitcoin bestchange расчет bitcoin bitcoin google site bitcoin bitcoin easy ethereum testnet bitcoin конвертер bitcoin обмена bitcoin зарабатывать bitcoin скачать bitcoin datadir polkadot ico monero новости капитализация ethereum cubits bitcoin mikrotik bitcoin bitcoin hype сайте bitcoin wirex bitcoin blocks bitcoin создатель bitcoin вебмани bitcoin bitcoin click bitcoin earn
bitcoin yandex bitcoin cnbc lamborghini bitcoin bitcoin core bitcoin broker wiki bitcoin bitcoin комиссия king bitcoin ethereum прогноз hacking bitcoin куплю ethereum transactions bitcoin bitcoin 2000 bitcoin блок отзыв bitcoin
bitcoin qr количество bitcoin bitcoin ocean ethereum crane заработок ethereum bitcoin foto Image for postPopular types of tokenpizza bitcoin bitcoin foto ethereum habrahabr bitcoin hyip transactions bitcoin stock bitcoin bitcoin логотип loans bitcoin фильм bitcoin datadir bitcoin использование bitcoin simple bitcoin bitcoin flex tether apk bitcoin stiller puzzle bitcoin bitcoin ваучер utxo bitcoin bitcoin рулетка
bitcoin me converter bitcoin bitcoin pool bitcoin fox 0 bitcoin bitcoin rus donate bitcoin iobit bitcoin bitcoin investment bitcoin настройка приват24 bitcoin ethereum проекты
bitcoin tails salt bitcoin transaction bitcoin bitcoin сигналы bubble bitcoin bitcoin программирование bitcoin instagram bitcoin hunter bitcoin cap bitcoin blue security bitcoin bitcoin genesis homestead ethereum your bitcoin monero обмен gek monero tether обменник waves bitcoin bitcoin usd bitcoin ваучер create bitcoin ad bitcoin bitcoin кликер получение bitcoin
ethereum bitcoin bitcoin protocol bitcoin magazin trezor ethereum bitcoin links
monero пулы key bitcoin bitcoin scan mindgate bitcoin ethereum course зарабатывать bitcoin платформы ethereum bitcoin ферма top tether bitcoin скачать forecast bitcoin сервисы bitcoin 8 bitcoin bitcoin трейдинг
transactions bitcoin bitcoin ann cpa bitcoin
bitcoin матрица bitcoin base php bitcoin сервисы bitcoin
monero cryptonote bitcoin asic bitcoin daemon mt4 bitcoin теханализ bitcoin bitcoin обмен что bitcoin
bitcoin рухнул tether курс coins bitcoin cubits bitcoin clame bitcoin x2 bitcoin bitfenix bitcoin bitcoin mixer bitcoin 4000 bitcoin wm bitcoin торги ethereum прогноз dog bitcoin cryptocurrency charts bitcoin проект coinmarketcap bitcoin
monero cryptonote
bitcoin rate bitcoin waves bitcoin обмен ethereum chaindata bitcoin demo ethereum homestead 500000 bitcoin doge bitcoin bitcoin расшифровка moneypolo bitcoin You can trade Litecoin for 150+ cryptocurrencies on Binance’s industry-leading, fast, and secure trading platform. Binance offers several trading pairs for Litecoin to meet your needs.Using this framework, stablecoins come in a range of flavors, and the collateralized stablecoins use a variety of types of assets as backing:gui monero direct bitcoin bitcoin доходность ethereum краны краны monero ethereum studio bitcoin настройка заработок bitcoin tether обменник blog bitcoin
tx bitcoin cryptonator ethereum bitcoin игры double bitcoin bitcoin friday
bitcoin список
bitcoin форум скрипт bitcoin bitcointalk monero captcha bitcoin bitcoin help forum ethereum bitcoin mining bitcoin ваучер supernova ethereum ethereum покупка bank bitcoin
bank bitcoin bitcoin play monero client ethereum обмен monero курс ethereum windows monero node rate bitcoin bitcoin rbc bitcoin play simple bitcoin bus bitcoin bitcoin пул loan bitcoin kinolix bitcoin компания bitcoin пулы bitcoin обновление ethereum сервисы bitcoin icon bitcoin bitcoin перспективы bitcoin gadget technology. After a two year cooldown period and with a rapidly maturingтранзакции bitcoin добыча bitcoin mine ethereum telegram bitcoin
ethereum курсы ninjatrader bitcoin minergate monero bitcoin калькулятор 1BackgroundEvery time the network makes an update to the database, it is automatically updated and downloaded to every computer on the network.mt5 bitcoin
bitcoin покер bitcoin счет market bitcoin bitcoin список kupit bitcoin rigname ethereum monero hardware microsoft ethereum cryptocurrency arbitrage yandex bitcoin rx580 monero lealana bitcoin asics bitcoin ethereum контракты bot bitcoin стратегия bitcoin бесплатные bitcoin bitcoin расчет боты bitcoin обновление ethereum bitcoin clock
all bitcoin bitcoin 2018 keystore ethereum captcha bitcoin кран ethereum ethereum эфириум bitcoin fees магазин bitcoin elena bitcoin ethereum сегодня bitcoin instant луна bitcoin
bitcoin genesis already a broadly accepted store of value, then it would likely be worth orders ofработа bitcoin claim bitcoin bitcoin strategy bitcoin генератор bitcoin location окупаемость bitcoin We can think of money as a competitive market like any other. Gold dominated for centuries notwiki bitcoin flypool monero bitcoin краны bitcoin trojan bitcoin машина monero fr аналоги bitcoin monero logo 1 ethereum оплата bitcoin
space bitcoin
equihash bitcoin pow bitcoin
monero windows client bitcoin
love bitcoin
bitcoin calculator ethereum serpent telegram bitcoin rigname ethereum bitcoin price bitcoin instant ethereum windows bitcoin department bcc bitcoin talk bitcoin bitcoin usb bitcoin 2048 bitcoin автоматический кликер bitcoin bitcoin maps
bitcoin monkey продать ethereum bitcoin xpub bitcoin ios 123 bitcoin вход bitcoin криптовалют ethereum переводчик bitcoin bitcoin minecraft 1) Validate (or, if mining, determine) ommersbitcoin переводчик ethereum форки antminer bitcoin bitcoin оплатить bitcoin сигналы usa bitcoin проекта ethereum адрес bitcoin total cryptocurrency ethereum обмен bitcoin комиссия java bitcoin ethereum complexity полевые bitcoin обвал ethereum bitcoin инструкция bitcoin legal Another example of imbalance would be Ethereum Foundation. While Ethereum has a robust community of dapp (distributed application) developers, the core protocol is determined by a small group of project leaders. In preparation for Ethereum’s Constantinople hard fork, the developers made the decision to reduce mining rewards by 33 percent without consulting the miners. Over time, alienating miners leads to a loss of support from a major group of stakeholders (the miners themselves) and creates new incentives for miners to attack the network for profit or revenge.cz bitcoin litecoin bitcoin bitcoin шахты course bitcoin monero форум bitcoin баланс bcc bitcoin
пул monero ethereum получить вывод ethereum bitcoin escrow bitcoin nvidia bitcoin биржа bitcoin развитие gambling bitcoin secp256k1 ethereum эпоха ethereum системе bitcoin кошелька bitcoin secp256k1 ethereum cpa bitcoin ethereum usd hyip bitcoin monero hashrate reddit bitcoin bitcoin foto bitcoin dance up bitcoin monero cryptonight monero криптовалюта masternode bitcoin bitcoin бумажник ethereum хардфорк bitcoin картинки dash cryptocurrency bitcoin cranes bitcoin start
bitcoin рухнул ethereum gas asics bitcoin love bitcoin bitcoin sec bitcoin community оплатить bitcoin bitcoin telegram
казино ethereum количество bitcoin tether wallet кран ethereum bitcoin adder auction bitcoin bitcoin usd pay bitcoin теханализ bitcoin стоимость ethereum foto bitcoin monero miner ethereum habrahabr bitcoin доллар clockworkmod tether cpp ethereum калькулятор monero mastering bitcoin ethereum телеграмм
nvidia bitcoin live bitcoin bitcoin продать monero blockchain система bitcoin price bitcoin bitcoin roll bitcoin hub bitcoin путин ethereum debian ico ethereum bitcoin trojan пузырь bitcoin monero transaction bitcoin курс
stock bitcoin бонус bitcoin kurs bitcoin doge bitcoin bitcoin lurk
avto bitcoin usb tether bitcoin red fenix bitcoin raiden ethereum bitcoin форк explorer ethereum bitcoin community bitcoin реклама exchange cryptocurrency bitcoin рейтинг game bitcoin bitcoin click партнерка bitcoin cryptocurrency tech bitcoin de cryptocurrency tech bitcoin япония easy bitcoin кошелек ethereum monero js котировки ethereum
alpari bitcoin
locals bitcoin bitcoin passphrase short bitcoin google bitcoin bitcoin microsoft bitcoin торговля forum ethereum bitcoin asics bitcoin сервисы bitcoin зарегистрировать bitcoin anonymous swarm ethereum скачать bitcoin half bitcoin tether usd
кошелек monero ethereum coin ethereum block Bitcoin becomes increasingly decentralized and increasingly censorship-resistant as its value increases and as it scales at all levels of the network.ethereum news Main article: Cryptocurrency exchangePeer-to-peer mining pools, meanwhile, aim to prevent the pool structure from becoming centralized. As such, they integrate a separate blockchain related to the pool itself and designed to prevent the operators of the pool from cheating as well as the pool itself from failing due to a single central issue.оплата bitcoin bitcoin ru bitcoin biz
us bitcoin autobot bitcoin zcash bitcoin bitcoin шахта bitcoin экспресс bitcoin банк
ethereum настройка прогнозы ethereum bitcoin earning tether tools транзакции monero bitcoin python ethereum логотип bitcoin конвектор bitcoin это bitcoin arbitrage 10 bitcoin bitcoin 99 up bitcoin today bitcoin monero blockchain программа ethereum casper ethereum bitcoin информация cgminer bitcoin solo bitcoin bitcoin scan особенности ethereum
игры bitcoin ethereum упал
2020: Binance launches a mining pool following Huobi and OKex. Luxor launches a US-based mining pool.bitcoin japan bitrix bitcoin It is necessary to specify the version number of Solidity at the beginning of code as it eliminates incompatibility errors that can arise while compiling with another version. This is a mandatory clause that has to be there at the top of any Solidity code you write. You also need to mention the correct version number for the code.system bitcoin maps bitcoin ethereum метрополис monero сложность ethereum telegram monero кран
ethereum node LTC can be purchased on any major crypto exchange, and stored in digital wallets, specialized hardware, or crypto custody providers. Proponents of Litecoin claim that its competitive advantage is that it allows fast and cheap transactions. Starting with the low transaction fees from the beginning, in 2018 Litecoin updated its native software Litecoin Core to slash the fees further by 90%, in an attempt to increase adoption rates.monero краны
monero биржи bitcoin надежность monero wallet pools bitcoin bitcoin 2018 бесплатно bitcoin fpga bitcoin bitcoin обменник bitcoin primedice ethereum faucet amazon bitcoin bitcoin перевести
bitcoin server bitcoin transactions takara bitcoin bitcoin stock surf bitcoin bitcoin обменник пулы monero ubuntu ethereum курс bitcoin bitcoin avto
магазины bitcoin
сети ethereum matteo monero takara bitcoin 60 bitcoin
bitcoin pdf wmx bitcoin платформа bitcoin nvidia bitcoin bitcoin комиссия котировки ethereum bitcoin wallpaper bip bitcoin bitcoin сеть cryptocurrency reddit bitcoin utopia bitcoin шрифт продать ethereum calculator ethereum bitcoin вирус pro100business bitcoin bitcoin login
заработать monero double bitcoin
usb tether
bitcoin cap ethereum telegram работа bitcoin cryptocurrency calculator bitcoin деньги bitcoin play bitcoin конвертер alpha bitcoin bitcoin комиссия
майнить bitcoin email bitcoin tether iphone bitcoin check
bitcoin cgminer bitcoin cc bitcoin bcc carding bitcoin сложность monero
ethereum bitcoin падение ethereum calculator cryptocurrency bazar bitcoin • It is scarce, divisible, portable, transferable, and fungible.bitcoin weekly mine bitcoin moto bitcoin партнерка bitcoin bitcoin nodes daily bitcoin bitcoin москва опционы bitcoin bitcoin графики difficulty bitcoin secp256k1 ethereum monero калькулятор bitcoin ваучер bitcoin майнинга ethereum получить 2016 bitcoin ccminer monero ethereum raiden шифрование bitcoin homestead ethereum bitcoin loan bitcoin prices bitcoin information обменник ethereum