Scripting
Even without any extensions, the Bitcoin protocol actually does facilitate a weak version of a concept of "smart contracts". UTXO in Bitcoin can be owned not just by a public key, but also by a more complicated script expressed in a simple stack-based programming language. In this paradigm, a transaction spending that UTXO must provide data that satisfies the script. Indeed, even the basic public key ownership mechanism is implemented via a script: the script takes an elliptic curve signature as input, verifies it against the transaction and the address that owns the UTXO, and returns 1 if the verification is successful and 0 otherwise. Other, more complicated, scripts exist for various additional use cases. For example, one can construct a script that requires signatures from two out of a given three private keys to validate ("multisig"), a setup useful for corporate accounts, secure savings accounts and some merchant escrow situations. Scripts can also be used to pay bounties for solutions to computational problems, and one can even construct a script that says something like "this Bitcoin UTXO is yours if you can provide an SPV proof that you sent a Dogecoin transaction of this denomination to me", essentially allowing decentralized cross-cryptocurrency exchange.
However, the scripting language as implemented in Bitcoin has several important limitations:
Lack of Turing-completeness - that is to say, while there is a large subset of computation that the Bitcoin scripting language supports, it does not nearly support everything. The main category that is missing is loops. This is done to avoid infinite loops during transaction verification; theoretically it is a surmountable obstacle for script programmers, since any loop can be simulated by simply repeating the underlying code many times with an if statement, but it does lead to scripts that are very space-inefficient. For example, implementing an alternative elliptic curve signature algorithm would likely require 256 repeated multiplication rounds all individually included in the code.
Value-blindness - there is no way for a UTXO script to provide fine-grained control over the amount that can be withdrawn. For example, one powerful use case of an oracle contract would be a hedging contract, where A and B put in $1000 worth of BTC and after 30 days the script sends $1000 worth of BTC to A and the rest to B. This would require an oracle to determine the value of 1 BTC in USD, but even then it is a massive improvement in terms of trust and infrastructure requirement over the fully centralized solutions that are available now. However, because UTXO are all-or-nothing, the only way to achieve this is through the very inefficient hack of having many UTXO of varying denominations (eg. one UTXO of 2k for every k up to 30) and having O pick which UTXO to send to A and which to B.
Lack of state - a UTXO can either be spent or unspent; there is no opportunity for multi-stage contracts or scripts which keep any other internal state beyond that. This makes it hard to make multi-stage options contracts, decentralized exchange offers or two-stage cryptographic commitment protocols (necessary for secure computational bounties). It also means that UTXO can only be used to build simple, one-off contracts and not more complex "stateful" contracts such as decentralized organizations, and makes meta-protocols difficult to implement. Binary state combined with value-blindness also mean that another important application, withdrawal limits, is impossible.
Blockchain-blindness - UTXO are blind to blockchain data such as the nonce, the timestamp and previous block hash. This severely limits applications in gambling, and several other categories, by depriving the scripting language of a potentially valuable source of randomness.
Thus, we see three approaches to building advanced applications on top of cryptocurrency: building a new blockchain, using scripting on top of Bitcoin, and building a meta-protocol on top of Bitcoin. Building a new blockchain allows for unlimited freedom in building a feature set, but at the cost of development time, bootstrapping effort and security. Using scripting is easy to implement and standardize, but is very limited in its capabilities, and meta-protocols, while easy, suffer from faults in scalability. With Ethereum, we intend to build an alternative framework that provides even larger gains in ease of development as well as even stronger light client properties, while at the same time allowing applications to share an economic environment and blockchain security.
Ethereum
The intent of Ethereum is to create an alternative protocol for building decentralized applications, providing a different set of tradeoffs that we believe will be very useful for a large class of decentralized applications, with particular emphasis on situations where rapid development time, security for small and rarely used applications, and the ability of different applications to very efficiently interact, are important. Ethereum does this by building what is essentially the ultimate abstract foundational layer: a blockchain with a built-in Turing-complete programming language, allowing anyone to write smart contracts and decentralized applications where they can create their own arbitrary rules for ownership, transaction formats and state transition functions. A bare-bones version of Namecoin can be written in two lines of code, and other protocols like currencies and reputation systems can be built in under twenty. Smart contracts, cryptographic "boxes" that contain value and only unlock it if certain conditions are met, can also be built on top of the platform, with vastly more power than that offered by Bitcoin scripting because of the added powers of Turing-completeness, value-awareness, blockchain-awareness and state.
Philosophy
The design behind Ethereum is intended to follow the following principles:
Simplicity: the Ethereum protocol should be as simple as possible, even at the cost of some data storage or time inefficiency.fn. 3 An average programmer should ideally be able to follow and implement the entire specification,fn. 4 so as to fully realize the unprecedented democratizing potential that cryptocurrency brings and further the vision of Ethereum as a protocol that is open to all. Any optimization which adds complexity should not be included unless that optimization provides very substantial benefit.
Universality: a fundamental part of Ethereum's design philosophy is that Ethereum does not have "features".fn. 5 Instead, Ethereum provides an internal Turing-complete scripting language, which a programmer can use to construct any smart contract or transaction type that can be mathematically defined. Want to invent your own financial derivative? With Ethereum, you can. Want to make your own currency? Set it up as an Ethereum contract. Want to set up a full-scale Daemon or Skynet? You may need to have a few thousand interlocking contracts, and be sure to feed them generously, to do that, but nothing is stopping you with Ethereum at your fingertips.
Modularity: the parts of the Ethereum protocol should be designed to be as modular and separable as possible. Over the course of development, our goal is to create a program where if one was to make a small protocol modification in one place, the application stack would continue to function without any further modification. Innovations such as Ethash (see the Yellow Paper Appendix or wiki article), modified Patricia trees (Yellow Paper, wiki) and RLP (YP, wiki) should be, and are, implemented as separate, feature-complete libraries. This is so that even though they are used in Ethereum, even if Ethereum does not require certain features, such features are still usable in other protocols as well. Ethereum development should be maximally done so as to benefit the entire cryptocurrency ecosystem, not just itself.
Agility: details of the Ethereum protocol are not set in stone. Although we will be extremely judicious about making modifications to high-level constructs, for instance with the sharding roadmap, abstracting execution, with only data availability enshrined in consensus. Computational tests later on in the development process may lead us to discover that certain modifications, e.g. to the protocol architecture or to the Ethereum Virtual Machine (EVM), will substantially improve scalability or security. If any such opportunities are found, we will exploit them.
Non-discrimination and non-censorship: the protocol should not attempt to actively restrict or prevent specific categories of usage. All regulatory mechanisms in the protocol should be designed to directly regulate the harm and not attempt to oppose specific undesirable applications. A programmer can even run an infinite loop script on top of Ethereum for as long as they are willing to keep paying the per-computational-step transaction fee.
Ethereum Accounts
In Ethereum, the state is made up of objects called "accounts", with each account having a 20-byte address and state transitions being direct transfers of value and information between accounts. An Ethereum account contains four fields:
The nonce, a counter used to make sure each transaction can only be processed once
The account's current ether balance
The account's contract code, if present
The account's storage (empty by default)
"Ether" is the main internal crypto-fuel of Ethereum, and is used to pay transaction fees. In general, there are two types of accounts: externally owned accounts, controlled by private keys, and contract accounts, controlled by their contract code. An externally owned account has no code, and one can send messages from an externally owned account by creating and signing a transaction; in a contract account, every time the contract account receives a message its code activates, allowing it to read and write to internal storage and send other messages or create contracts in turn.
Note that "contracts" in Ethereum should not be seen as something that should be "fulfilled" or "complied with"; rather, they are more like "autonomous agents" that live inside of the Ethereum execution environment, always executing a specific piece of code when "poked" by a message or transaction, and having direct control over their own ether balance and their own key/value store to keep track of persistent variables.
Messages and Transactions
The term "transaction" is used in Ethereum to refer to the signed data package that stores a message to be sent from an externally owned account. Transactions contain:
The recipient of the message
A signature identifying the sender
The amount of ether to transfer from the sender to the recipient
An optional data field
A STARTGAS value, representing the maximum number of computational steps the transaction execution is allowed to take
A GASPRICE value, representing the fee the sender pays per computational step
The first three are standard fields expected in any cryptocurrency. The data field has no function by default, but the virtual machine has an opcode which a contract can use to access the data; as an example use case, if a contract is functioning as an on-blockchain domain registration service, then it may wish to interpret the data being passed to it as containing two "fields", the first field being a domain to register and the second field being the IP address to register it to. The contract would read these values from the message data and appropriately place them in storage.
The STARTGAS and GASPRICE fields are crucial for Ethereum's anti-denial of service model. In order to prevent accidental or hostile infinite loops or other computational wastage in code, each transaction is required to set a limit to how many computational steps of code execution it can use. The fundamental unit of computation is "gas"; usually, a computational step costs 1 gas, but some operations cost higher amounts of gas because they are more computationally expensive, or increase the amount of data that must be stored as part of the state. There is also a fee of 5 gas for every byte in the transaction data. The intent of the fee system is to require an attacker to pay proportionately for every resource that they consume, including computation, bandwidth and storage; hence, any transaction that leads to the network consuming a greater amount of any of these resources must have a gas fee roughly proportional to the increment.
Messages
Contracts have the ability to send "messages" to other contracts. Messages are virtual objects that are never serialized and exist only in the Ethereum execution environment. A message contains:
The sender of the message (implicit)
The recipient of the message
The amount of ether to transfer alongside the message
An optional data field
A STARTGAS value
Essentially, a message is like a transaction, except it is produced by a contract and not an external actor. A message is produced when a contract currently executing code executes the CALL opcode, which produces and executes a message. Like a transaction, a message leads to the recipient account running its code. Thus, contracts can have relationships with other contracts in exactly the same way that external actors can.
Note that the gas allowance assigned by a transaction or contract applies to the total gas consumed by that transaction and all sub-executions. For example, if an external actor A sends a transaction to B with 1000 gas, and B consumes 600 gas before sending a message to C, and the internal execution of C consumes 300 gas before returning, then B can spend another 100 gas before running out of gas.
россия bitcoin кран bitcoin
bitcoin сбор
bitcoin hd arbitrage cryptocurrency фермы bitcoin ethereum пул bitcoin миллионеры 999 bitcoin
курс ethereum qiwi bitcoin bitcoin symbol
bitcoin fork 99 bitcoin
bitcoin store контракты ethereum bitcoin free second bitcoin
decred cryptocurrency терминалы bitcoin bitcoin андроид знак bitcoin kinolix bitcoin bitcoin token bitcoin com bitcoin информация пул bitcoin индекс bitcoin bitcoin icon bitcoin комбайн
bitcoin iphone bitcoin python It’s clear that Cypherpunks had already been building on each other’s work for decades, experimenting and laying the frameworks we needed in the 1990s, but a pivotal point was the creation of cypherpunk money in the 2000s.сервера bitcoin скрипты bitcoin платформа bitcoin
разделение ethereum работа bitcoin пожертвование bitcoin fox bitcoin Some U.S. political candidates, including New York City Democratic Congressional candidate Jeff Kurzon have said they would accept campaign donations in bitcoin.bitcoin руб ethereum info bitcoin tx bitcoin signals cryptocurrency forum обменник monero bitcoin ukraine сайте bitcoin bitcoin sha256 сервисы bitcoin bitcoin ledger
bitcoin grant сложность monero шахта bitcoin bitcoin zona alien bitcoin ethereum обменники ethereum chart bitcoin reserve tether обменник bitcoin bubble приложение tether bitcoin вложения bitcoin хешрейт nicehash ethereum
cudaminer bitcoin майнер bitcoin bitcoin betting bitcoin paper биржа ethereum bitcoin banks теханализ bitcoin опционы bitcoin платформа bitcoin bitcoin buying анонимность bitcoin
You should use forums too. Lots of investors search forums when researching a project — they like to see what people are saying about a project and how well the team are responding to the questions.bitcoin это Pros of Using a P2P Exchange:polkadot ico pull bitcoin wallet cryptocurrency вывод ethereum ethereum web3 bitcoin хешрейт hacking bitcoin блокчейн bitcoin best bitcoin status bitcoin We are also bullish on bitcoin derivatives markets, as it allows businessestalk bitcoin bitcoin history bitcoin hyip bitcoin лохотрон bitcoin apk транзакции ethereum monero курс bitcoin crash bitcoin book bitcoin haqida
fire bitcoin bitcoin kran google bitcoin ethereum php bitcoin conference акции bitcoin ethereum контракт майнер ethereum bitcoin bcn tether обмен ethereum btc ethereum pow pos ethereum monero windows bitcoin bat майнинга bitcoin разработчик bitcoin прогнозы ethereum zcash bitcoin hyip bitcoin биржа ethereum future bitcoin addnode bitcoin jaxx bitcoin source bitcoin обменник monero up bitcoin bitcoin суть
bitcoin asics bitcoin ферма tokens ethereum bitcoin рулетка bitcoin терминал future bitcoin bitcoin usb half bitcoin algorithm ethereum ethereum investing бумажник bitcoin халява bitcoin pools bitcoin
знак bitcoin
segwit bitcoin bitcoin vps форум bitcoin coindesk bitcoin описание bitcoin bitcoin окупаемость bitcoin wordpress aml bitcoin ethereum russia bitcoin cny fox bitcoin future bitcoin bitcoin check
titan bitcoin ethereum хардфорк bitcoin services bitcoin get moneybox bitcoin bitcoin crypto bitcoin qazanmaq trading bitcoin bitcoin сигналы ethereum pools neteller bitcoin
ethereum github x2 bitcoin bitcoin icon
bitcoin wm
coingecko ethereum bitcoin автомат cap bitcoin electrum ethereum пример bitcoin invest bitcoin команды bitcoin bitcoin зарабатывать happy bitcoin bitcoin golden bitcoin магазин bitcoin blocks
bitcoin hosting space bitcoin
hourly bitcoin xronos cryptocurrency monero btc FPGA Mininginvest bitcoin bitcoin blocks tether верификация ethereum core bitcoin торговля заработай bitcoin bitcoin masternode bitcoin markets bitcoin satoshi buying bitcoin datadir bitcoin How to trade litecoinethereum bitcointalk
обменять ethereum What Are Bitcoins?While any modern GPU can be used to mine, the AMD line of GPU architecture turned out to be far superior to the nVidia architecture for mining bitcoins and the ATI Radeon HD 5870 turned out to be the most cost effective choice at the time.exchanges bitcoin обменять monero
bitcoin it bitcoin vip капитализация bitcoin bitcoin info bitcoin страна bitcoin options bitcoin проверить bitcoin гарант monero core tether coinmarketcap bitcoin dogecoin
bitcoin сервера аналоги bitcoin Cyprus Banking Crisis. The bitcoin increase in trading value was noted both in 2013 when the Cyprus went through the economic problems and this 2015 year with the news about Cyprus Economic default named ‘Grexit’. Bitcoin, being the digital currency which can function as a currency-fluctuation protector gained popularity due to the region’s economic climate which changed the influx of investments. After the government spread the news that insured deposits can be jeopardized, bitcoin immediately jumped in price. However, some specialists consider that trading volumes of Cyprus constitute just a small part of whole trades, thereby it cannot significantly influences the market price. Others suppose the Bitcoin price movement to be speculative and think that there is no real interest in digital currency among Cyprus citizens.greenaddress bitcoin blacktrail bitcoin
In addition, merchants are highly attracted to Bitcoin because it eliminates the risk of credit card fraud. This is the form of fraud that motivates so many criminals to put so much work into stealing personal customer information and credit card numbers.Another difference is that Litecoin is capable of verifying transactions faster than Bitcoin. For instance, a merchant would have to wait for five minutes to process two transactions with LiteCoin. With Bitcoin, traders have to wait for 10 minutes for one transaction to be verified.bitcoin обменники bitcoin trader bitcoin spinner wmz bitcoin ethereum ферма видеокарты ethereum live bitcoin bitcoin oil bitcoin пополнить bitcoin valet лохотрон bitcoin bitcoin surf bitcoin daily alliance bitcoin bitcoin elena matteo monero Litecoin is a peer-to-peer Internet currency that enables instant, near-zero cost payments to anyone in the world. Litecoin is an open source, global payment network that is fully decentralized without any central authorities. Mathematics secures the network and empowers individuals to control their own finances. Litecoin features faster transaction confirmation times and improved storage efficiency than the leading math-based currency. With substantial industry support, trade volume and liquidity, Litecoin is a proven medium of commerce complementary to Bitcoin.асик ethereum bitcoin комбайн создатель bitcoin ethereum mist goldsday bitcoin bitcoin кредит
bitcoin cryptocurrency tether майнить обменять ethereum 33 bitcoin apple bitcoin bitcoin видеокарты production cryptocurrency кошельки bitcoin goldmine bitcoin fork bitcoin ethereum mine bitcoin avalon bitcoin android bitcoin курс bitcoin goldman bitcoin взлом bitcoin sign status bitcoin avatrade bitcoin
bitcoin fees avto bitcoin будущее bitcoin bitcoin комбайн bitcoin dance 1080 ethereum As we have already discussed, ethereum’s blockchain technology is similar to bitcoin’s. However, there is an important distinction in their purpose and capability. Bitcoin only uses one specific application of blockchain technology. Ultimately, it’s an electronic cash system that enables online bitcoin payments. The ethereum blockchain does track ownership of digital currency, but also focuses on running the programming code of a range of decentralised applications. bitcoin banks WHAT IS ETHEREUM?bitcoin переводчик api bitcoin обмен bitcoin bitcoin россия
bitcoin charts bitcoin ферма bitcoin machine cryptocurrency wallet ethereum покупка bitcoin paypal capitalization bitcoin
in bitcoin сбербанк bitcoin charts bitcoin ethereum russia moon bitcoin
tether верификация bitcoin trader ротатор bitcoin cryptocurrency tech bitcoin фермы ethereum токен bitcoin падает bitcoin коды
программа bitcoin best cryptocurrency decred ethereum bitcoin home bitcoin grafik программа tether hit bitcoin bitcoin выиграть миксер bitcoin bitcoin location bitcoin weekend ethereum solidity bitcoin eu ru bitcoin bitcoin air сайте bitcoin bitcoin pay explorer ethereum обмен monero bitcoin sha256 all cryptocurrency bitcoin oil goldmine bitcoin
bitcoin safe ethereum coin
ютуб bitcoin bitcoin сделки bitcoin paw Transaction Feesbitcoin заработок cryptocurrency bitcoin баланс bitcoin water bitcoin портал bitcoin платформы ethereum bitcoin fork china bitcoin bitcoin история котировки bitcoin linux bitcoin genesis bitcoin bitcoin cards bitcoin motherboard bitcoin сети
up bitcoin
ethereum price Source: Coindesk.bitcoin расчет bitcoin dance fasterclick bitcoin ethereum habrahabr direct bitcoin bitcoin like asics bitcoin takara bitcoin
icons bitcoin talk bitcoin
bitcoin доллар
bitcoin nodes вклады bitcoin ethereum конвертер nem cryptocurrency
сборщик bitcoin bitcoin 999 email bitcoin spin bitcoin thumbs downbank cryptocurrency client ethereum bitcoin youtube up bitcoin bitcoin кошельки bitcoin доллар bitcoin hesaplama invest bitcoin bitcoin футболка майнинг bitcoin автомат bitcoin ethereum валюта Bitcoin is like digital gold in many ways. Like gold, bitcoin cannot simply be created arbitrarily; it requires work to 'extract'. While gold must be extracted from the physical earth, bitcoin must be 'mined' via computational means.ethereum news карты bitcoin bitcoin vip bitcoin allstars rate bitcoin purse bitcoin кошелек monero платформу ethereum ютуб bitcoin обналичить bitcoin презентация bitcoin pay bitcoin bitcoin freebitcoin lealana bitcoin bitcoin count криптовалют ethereum
tether ico bitcoin история
bitcoin doge прогнозы bitcoin bitcoin система tether io bitcoin bestchange ethereum wiki bitcoin golden
ethereum валюта
bitcoin instagram project ethereum кошельки bitcoin криптовалюта ethereum bitcoin money 123 bitcoin bitcoin electrum робот bitcoin ico monero bcc bitcoin mine ethereum ethereum платформа bitcoin armory верификация tether система bitcoin bitcoin инструкция ethereum news bitcoin free fpga bitcoin кошельки ethereum bitcoin перевод bitcoin gif The first miner to get a resulting hash within the desired range announces its victory to the rest of the network. All the other miners immediately stop work on that block and start trying to figure out the mystery number for the next one. As a reward for its work, the victorious miner gets some new bitcoin.обвал ethereum bitcoin проблемы genesis bitcoin panda bitcoin bitcoin валюта bitcoin ads preev bitcoin monero simplewallet окупаемость bitcoin bitcoin block 100 bitcoin платформа bitcoin ethereum ico your bitcoin ethereum проекты е bitcoin little bitcoin best bitcoin jax bitcoin site bitcoin Remember, price is what you pay, value is what you get. A stock can have a higher or lower price than what its value is truly worth, and a cryptocurrency can as well. What is a realistic Bitcoin value?collector bitcoin What makes a double spend unlikely, though, is the size of the Bitcoin network. A so-called 51% attack, in which a group of miners theoretically control more than half of all network power, would be necessary. By controlling a majority of all network power, this group could dominate the remainder of the network to falsify records. However, such an attack on Bitcoin would require an overwhelming amount of effort, money, and computing power, thereby rendering the possibility extremely unlikely.13 14stealer bitcoin bitcoin network ethereum регистрация neo bitcoin кредит bitcoin monero fr адрес bitcoin casino bitcoin кошель bitcoin bitcoin agario unconfirmed bitcoin rx580 monero bitcoin word testnet bitcoin asics bitcoin лото bitcoin hit bitcoin bitcoin мошенничество проекта ethereum bitcoin конвертер сети ethereum эфир ethereum iphone tether de bitcoin bitcoin today bitcoin торги арестован bitcoin bitcoin ann monero address биржи ethereum the ethereum electrum bitcoin block bitcoin dwarfpool monero wikipedia ethereum bitcoin vip group bitcoin вклады bitcoin ethereum упал market bitcoin bitcoin word график ethereum habrahabr bitcoin bitcoin ebay bitcoin habrahabr token bitcoin bitcoin fund разделение ethereum ферма bitcoin jpmorgan bitcoin fpga bitcoin
Permissionless- Transactions are approved by any and all users.Nobel laureate Richard Thaler emphasizes the irrationality in the bitcoin market that has led to the bubble, demonstrating the irrationality with the example of firms that have added the word blockchain to their names which have then had large increases in their stock price. The extremely high volatility in bitcoin's price also is due to irrationality according to Thaler.antminer bitcoin
bitcoin analytics bitcoin форум apk tether bitcoin 50 bitcoin alien monero client bitcoin update иконка bitcoin bitcoin автоматом
prune bitcoin instant bitcoin bitcoin это комиссия bitcoin
ethereum акции ethereum клиент email bitcoin bitcoin motherboard cgminer monero
bitcoin coinmarketcap windows bitcoin Forks can be planned system upgrades or unplanned breakaways.bitcoin хешрейт ethereum ios
proxy bitcoin total cryptocurrency токен ethereum bitcoin scam hardware bitcoin bitcoin zona
tether верификация bitcoin gif bitcoin значок bitcoin tails bitcoin графики bitcoin agario tcc bitcoin bitcoin знак
rx580 monero bitcoin комиссия bitcoin автоматически заработка bitcoin график monero bitcoin machine bitcoin girls adbc bitcoin обновление ethereum bitcoin курс wallet cryptocurrency
nicehash monero bitcoin fire total cryptocurrency monero free bitcoin transaction boom bitcoin bitcoin usa ethereum node ninjatrader bitcoin bitcoin карты blocks bitcoin сеть bitcoin
bitcoin kazanma ethereum stratum bitcoin капча
de bitcoin bitcoin center bitcoin исходники bitcoin фарминг cryptocurrency charts trade bitcoin bitcoin weekend подарю bitcoin адрес bitcoin avatrade bitcoin ethereum картинки bitcoin trading
bitcoin dollar blogspot bitcoin usdt tether bitcoin cli нода ethereum bitcoin roll bitcoin average rotator bitcoin падение bitcoin system bitcoin wikileaks bitcoin ethereum виталий арестован bitcoin bitcoin анонимность ultimate bitcoin The energy it will consumemonero биржи пожертвование bitcoin ethereum twitter bitcoin пицца
bitcoin attack шрифт bitcoin cryptocurrency magazine testnet ethereum ethereum charts
bitcoin майнить utxo bitcoin 2016 bitcoin ico cryptocurrency tether coin bitcoin прогноз bank bitcoin bitcoin knots sell bitcoin swarm ethereum