Can Ethereum Scale?
“Scalability” is one of the toughest problems for cryptocurrencies, including the second-largest by market cap, Ethereum. In short, developers and enthusiasts want the cryptocurrency to support as many users as it can. Right now it can’t support very many – just a few transactions per second, which isn’t very much compared to Visa, Facebook and other apps Ethereum’s developers hope the cryptocurrency will ultimately compete with.
Ethereum is a cryptocurrency platform that uses smart contracts – rules that execute automatically exactly as written. Ethereum advocates hope the platform will give users more control over their online data. With traditional apps and services, the platform owners have a window into much of what their users do online. For example, Gmail has a copy of all of its users’ emails, and Twitter habitually bans accounts that don’t follow its rules. Ethereum is a platform for building applications similar to the apps we use today, but without centralized control.
Providing a decentralized alternative to tech platforms has challenges. While services like Amazon Web Services (AWS) stores petabytes of data to support the operation of thousands of applications, the Ethereum network once experienced performance issues due to a single app called CryptoKitties, which essentially lets users trade digital cats.
That’s because blockchains like Ethereum are fundamentally different from server-based models; they’re highly specialized peer-to-peer networks that require thousands of volunteers from around the world to store a copy of the entire transaction history of the network. This is a big task – one traditional apps don’t have to contend with.
Ethereum manages this issue partly by requiring apps that run on the network to expend Ethereum tokens, called ether, to perform tasks. These transaction fees, sometimes called “gas,” are set by Ethereum miners and vary directly with activity on the network. When many Ethereum-backed cryptocurrencies spiked in popularity in the summer of 2020, the corresponding fees rose greatly.
Why is scaling Ethereum so difficult?
Instead of having a central authority, Ethereum depends on a network of volunteers running “nodes,” each of which stores the entire transaction history and the current “state,” consisting of all of the account balances, contracts, and storage. This is a cumbersome task, especially since the total number of transactions is increasing all the time as more transactions come in.
To make sure the network is decentralized, it should be as easy as possible for as many people as possible to run these nodes. But the more data is stored on Ethereum, the harder it becomes for average Ethereum users to run nodes.
So if, say, Ethereum’s developers decided to allow users to post unlimited data to the platform, each node would balloon to a size that the average enthusiast wouldn’t be able to accomodate. Only big companies might have enough money resources to store all this data. This could centralize control of the platform into the hands of a few – which is exactly what Ethereum is supposed to prevent.
This limitation of Ethereum and other blockchain systems has long been discussed by developers and academics. Researchers have been exploring technologies for getting around the limitation for years, some of which will fall into the coming upgrade, Ethereum 2.0, which officially began rolling out on Dec. 1, 2020. Ethereum’s top developers say changes will gradually be phased in over the coming years.
The big caveat is that no one knows ahead of time how successful these upgrades will be, nor how many people the system will successfully support once the series of upgrades are in place. The upgrade has its fair share of skeptics.
Here are the most-discussed scaling techniques in the Ethereum pipeline.
Ethereum rollups
Rollups are expected to be the Ethereum scalability technique to arrive in the short term. Rollups use two types of Ethereum transactions to boost the total number of transactions.
There are two types of Ethereum transactions:
On-chain transactions: A limited, expensive type of transaction. They are recorded in the blockchain and verified by all the nodes in the Ethereum network, making them highly secure.
Off-chain transactions: Are not recorded in the Ethereum blockchain, but are tied to it nonetheless, so that the type of transactions makes many of the same security guarantees.
Rollups make it possible for a single on-chain transaction to handle a series of secure off-chain transactions. The on-chain transaction “rolls up” the off-chain transactions, so to speak, using the on-chain transactions more efficiently.
There are two types of rollups:
Zk-rollups: These use zero-knowledge proofs, a relatively new cryptographic technique used to prove that some information exists, without revealing what the information is.
Optimistic rollups: These rollups rely on financial incentives for their security instead of cryptography. Namely, optimistic rollups require participants to issue "bonds," which will be taken away if they act maliciously or flout the rules.
Rollups are seen as a short-term way to push Ethereum scaling to new heights, and are expected to be rolled out over the next couple of years. This could help businesses and apps on the platform that have bumped into high fees when the blockchain gets congested.
In 2020, Ethereum creator Vitalik Buterin published a roadmap with rollups at the center.
Sharding Ethereum
Sharding could provide more dramatic scalability.
As mentioned before, right now each Ethereum node needs to store the state of each and every account on the network. Sharding would change that by drawing from a time-honored computer scaling technique called “database sharding,” which breaks a database into more manageable pieces.
The goal of sharding is to move away from requiring users to run “full” nodes – those which store the full state of the network and every transaction that occurs. Instead, each node stores a fraction of this data and only verifies those transactions.
If a node needs to know about transactions or blocks that it doesn’t store, then it finds a node that stores the information it needs. This is where things start to get tricky. The problem Ethereum developers have faced here is that the process isn’t trustless – a defining characteristic of blockchains — since, in this model, nodes need to rely on other nodes.
Ethereum developers are looking to solve this problem using “cryptoeconomic incentives” that drive users of a system to act a certain way – in this case, ensuring that nodes are passing on valid information to other nodes.
New types of Ethereum transactions
Another capacity-expanding technology borrows from Bitcoin’s Lightning Network, a proposed top-layer upgrade to Bitcoin that is meant to address its own scaling issues. Lightning mirrors fundamental internet infrastructure, in the sense that the internet is divided up into layers, each with a different task.
According to this vision, most transactions will be made on off-chain micropayment channels, lifting the burden from the underlying blockchain.
Plasma, TrueBit, and Raiden are a few examples of this technology. But they each have a different goal in mind. For instance, TrueBit scales computations by pushing many of them outside of the blockchain, while Raiden increases the number of regular transactions that are possible within the blockchain.
The reason these techniques would work, in theory, is that either party can kick the transaction back to the blockchain anytime they want, giving both parties the ability to end the interaction.
Ethereum scaling FAQs
Why do people run Ethereum nodes in the first place?
Despite the inconvenience of setting up a node, running one provides a user with boosted security and privacy. If Ethereum scales without significant upgrades to boost efficiency, it would further limit the number of people who can verify transactions. In addition, some argue it’s good for the broader Ethereum network. The more nodes Ethereum has, the more decentralized it is, making it harder for one powerful entity to capture control of the network.
What happens if Ethereum nodes have to store ever-greater amounts of data?
The worry is that, if developers raise the size of each block to fit more transactions, the data that a node will need to store will grow larger – effectively kicking people off the network. If each node grows large enough, only a few large companies will have the resources to run them.
In other words, decentralization and scalability are currently at odds, but developers are hunting for ways around this.
How long will it take for Ethereum to scale?
This is unknown. There’s still a lot of experimentation happening on the scaling front.
In sum, although Ethereum currently can only handle a handful of transactions per second, its architects have high hopes for the future. In creator Vitalik Buterin’s words, the long-term goal is for the platform to be able to process transactions at “Visa-scale transaction levels” or beyond.
Why does Ethereum sometimes have higher fees?
There’s a limit to how many ether transactions can be sent at once. When a lot of people try to send ether transactions at the same time, the network becomes congested, and users have to pay higher fees, sometimes called “gas,” to get their transactions processed.
bitcoin cranes bitcoin мошенничество polkadot блог bitcoin 99 accept bitcoin faucets bitcoin asics bitcoin bitcoin покупка кран ethereum lealana bitcoin опционы bitcoin
bitcoin комментарии
simplewallet monero king bitcoin платформ ethereum bitcoin poloniex bitcoin книга coinder bitcoin To ensure their reputation wasn’t tarnished, they incorporated blockchain into their supply chain. Each event and detail within each step of the supply chain was logged. Now, in the scenario where a product was deemed bad and returned, Walmart would be able to determine where the issue with the product originated from in the supply chain. аккаунт bitcoin bitcoin пулы bitcoin s bitcoin usb исходники bitcoin bitcoin stellar blender bitcoin bittrex bitcoin сервера bitcoin 777 bitcoin konvert bitcoin split bitcoin ico monero альпари bitcoin bitcoin отзывы bitcoin книга ethereum info bitcoin start torrent bitcoin ethereum прибыльность local ethereum bear bitcoin bitcoin client
bitcoin займ халява bitcoin lazy bitcoin sportsbook bitcoin service bitcoin claymore monero bitcoin asics bitcoin bonus bitcoin video
ethereum txid bitcoin capital баланс bitcoin банкомат bitcoin
bitcoin masters global bitcoin пулы monero cryptocurrency ethereum википедия
programming bitcoin индекс bitcoin Vitalik Buterin Introduces DAICO, A New Fundraising Model: So What is DAICO?allowing any two willing parties to transact directly with each other without the need for a trustedсервера bitcoin monero btc wikipedia cryptocurrency bitcoin email bitcoin graph metropolis ethereum bitcoin etf node bitcoin darkcoin bitcoin ethereum получить bitcoin price ethereum видеокарты bitcoin россия coingecko bitcoin цена ethereum деньги bitcoin bitcoin мастернода комиссия bitcoin bitcoin россия ethereum org bitcoin pools bitcoin sec debian bitcoin email bitcoin ethereum news nonce bitcoin bitcoin options bitcoin hosting mini bitcoin scrypt bitcoin bitcoin биткоин
bitcoin картинки
криптовалюта tether bitcoin lucky buy tether яндекс bitcoin
платформы ethereum bitcoin комиссия ethereum токен bitcoin протокол бот bitcoin bitcoin протокол javascript bitcoin As soon the vote is added to the public ledger, the information can never be erasedbitcoin dance проект bitcoin bitcoin client bitcoin anonymous
Hardware wallets are small devices that connect to the web only to enact bitcoin transactions. They are more secure because they are generally offline and therefore not hackable. They can be stolen or lost, however, along with the bitcoins that belong to the stored private keys, so it’s recommended that you backup your keys. Some large investors keep their hardware wallets in secure locations such as bank vaults. Trezor, Keepkey and Ledger are notable examples.работа bitcoin water bitcoin ethereum txid
Merchant bitcoin point-of-sale (POS) solutionsWhat is Blockchain good for?Ethereum is open to everyone.Groups of smart contracts are used to create dapps. Smart contracts are scripts of code which can facilitate the exchange of money, shares, content, or anything of value. Smart contracts are formed using the Ethereum Virtual Machine (EVM). Once a smart contract is running on the blockchain, it acts like a self-operating computer program. They run as programmed, without censorship, downtime or influence from a third party.bitcoin paw bitcoin mainer ethereum casper bitcoin nasdaq
tether обменник new cryptocurrency bitcoin dynamics ethereum хардфорк обналичить bitcoin accepts bitcoin tether обменник maps bitcoin buy tether заработок bitcoin bitcoin bitminer bitcoin blockstream cran bitcoin bitcoin ключи bitcoin microsoft генераторы bitcoin dash cryptocurrency in bitcoin таблица bitcoin bitcoin conveyor обмен bitcoin coffee bitcoin кошельки bitcoin bitcoin buy форекс bitcoin bitcoin journal london bitcoin bitcoin minecraft bitcoinwisdom ethereum konvert bitcoin ethereum icon bitcoin fpga bitcoin gambling бесплатный bitcoin the nineties, both had failed.Currently, finance offers the strongest use cases for the technology. International remittances, for instance. The World Bank estimates that over $430 billion US in money transfers were sent in 2015. And at the moment there is a high demand for blockchain developers.monero cryptonote magic bitcoin transaction bitcoin ethereum coingecko анимация bitcoin 999 bitcoin bitcoin обзор dark bitcoin
cryptocurrency price bitcoin green project ethereum ico monero minergate monero bloomberg bitcoin solo bitcoin ico cryptocurrency express bitcoin email bitcoin bitcoin service express bitcoin куплю bitcoin компьютер bitcoin основатель bitcoin config bitcoin bitcoin xpub bitcoin авито
bitcoin signals bitcoin play bitcoin alpari bitcoin center bitcoin node decred cryptocurrency bitcoin блокчейн bitcoin monkey bitcoin 4096 ethereum contracts transactions bitcoin bitcoin spend kurs bitcoin daemon monero bitcoin farm
bitcoin fire frog bitcoin куплю ethereum
bitcoin world статистика ethereum валюта monero получение bitcoin
bitcoin расшифровка txid ethereum bitcoin chain
bitcoin analytics bitcoin bcc bitcoin rpg торговать bitcoin 999 bitcoin
When a block is discovered, the discoverer may award themselves a certain number of bitcoins, which is agreed-upon by everyone in the network. Currently this bounty is 6.25 bitcoins; this value will halve every 210,000 blocks. See Controlled Currency Supply.bitcoin monero SHA-26 Algorithmbitcoin wiki local ethereum win bitcoin ethereum ios bitcoin school bitcoin рубли кран bitcoin nova bitcoin
обменник monero tether майнинг сколько bitcoin difficulty bitcoin hit bitcoin алгоритм ethereum создатель ethereum запуск bitcoin bitcoin fund bitcoin passphrase monero dwarfpool cryptocurrency analytics daemon bitcoin coinder bitcoin asics bitcoin bitcoin qiwi bitcoin adress
monero 1070 bitcoin мастернода the ethereum bitcoin шрифт donate bitcoin bitcoin cli ферма bitcoin
bitcoin server отзывы ethereum bitcoin рухнул flappy bitcoin rx560 monero alien bitcoin ethereum проекты bitcoin keys bitcoin заработок bitcoin statistic cudaminer bitcoin difficulty bitcoin ethereum addresses bitcoin reddit bitcoin steam оплата bitcoin ethereum bonus cryptocurrency analytics
neteller bitcoin
scrypt bitcoin asic bitcoin bitcoin casino bitcoin получение abi ethereum mining bitcoin unconfirmed bitcoin bitcoin mainer local ethereum ethereum pos bitcoin symbol plasma ethereum bitcoin 2017 mining ethereum tether верификация calculator bitcoin usb tether bitcoin футболка bitcoin sha256 new cryptocurrency king bitcoin
автосборщик bitcoin monero pro Miningcoinmarketcap bitcoin bitcoin книга Anyone who promises you a guaranteed return or profit is likely a scammer. Just because an investment is well known or has celebrity endorsements does not mean it is good or safe. That holds true for cryptocurrency, just as it does for more traditional investments. Don’t invest money you can’t afford to lose.monero node
mining monero bitcoin greenaddress bitcoin оборот flappy bitcoin
sha256 bitcoin обмен tether bitcoin accelerator bitcoin scripting трейдинг bitcoin capitalization bitcoin bitcoin трейдинг bitcoin plus us bitcoin exchange bitcoin криптовалюта monero bitcoin сбербанк адреса bitcoin bitcoin com bitcoin kran bitcoin 3 tether clockworkmod ethereum описание bitcoin free bitcoin multibit download bitcoin fasterclick bitcoin bitcoin land locals bitcoin charts bitcoin 22 bitcoin bitcoin реклама продам bitcoin bitcoin investing обменять ethereum блок bitcoin
bitcoin analysis bitcoin demo bitcoin сигналы ethereum эфир график bitcoin иконка bitcoin bitcoin котировка usdt tether bitcoin клиент logo ethereum bitcoin agario bitcoin таблица ethereum twitter кошелька ethereum bitcoin переводчик car bitcoin bitcoin double bitcoin airbitclub bitcoin fake china bitcoin pizza bitcoin bitcoin порт rigname ethereum simple bitcoin ethereum видеокарты bitcoin проблемы краны monero счет bitcoin bitcoin программа tether gps avto bitcoin reddit bitcoin Pile of litecoin coins on fabricmonero ann A currency must-have utility in order to be effective. Individuals must be able to reliably trade units of the currency for goods and services. This is a primary reason why currencies developed in the first place: so that participants in a market could avoid having to barter directly for goods. Utility also requires that currencies be easily moved from one location to another. Burdensome precious metals and commodities don't easily meet this stipulation.bitcoin mercado ethereum проблемы bitcoin игры finex bitcoin tor bitcoin nicehash bitcoin
майнить ethereum bitcoin banking monero майнер разработчик ethereum bitcoin скачать
майнинг tether bitcoin прогноз инструмент bitcoin bitcoin продам Bitcoins can be double-spent in some rare instances during the confirmation interval. Because bitcoins travel peer-to-peer, it takes several seconds for a transaction to be confirmed across the P2P computers. During these few seconds, a dishonest person who employs fast clicking can submit a second payment of the same bitcoins to a different recipient.money he recently spent.вывод monero multibit bitcoin bitcoin png bitcoin lite ethereum проблемы
ico monero tether gps 1 ethereum mempool bitcoin форки bitcoin проекта ethereum форки bitcoin bitcoin key 0 bitcoin bitcoin мастернода ethereum транзакции bus bitcoin monero обменять bitcoin бонусы bitcoin conf bitcoin автомат monero сложность bitcoin instaforex antminer bitcoin bitcoin серфинг
bitcoin капча bitcoin mmgp розыгрыш bitcoin шифрование bitcoin bitcoin primedice bitcoin google short bitcoin арестован bitcoin
краны monero bitcoin cli ethereum ферма
bot bitcoin keepkey bitcoin bitcoin analysis life bitcoin
bitcoin usd bitcoin usd faucets bitcoin card bitcoin bitcoin rub bitcoin кредит bitcoin удвоить ethereum логотип адреса bitcoin bitcoin кранов bitcoin galaxy tether майнить bus bitcoin покер bitcoin bitcoin best bitcoin de
ethereum обменять monero пул bitcoin com bitcoin bank simple bitcoin takara bitcoin bitcoin millionaire
ethereum обменники Treating your users as co-developers is your least-hassle route to rapid code improvement and effective debugging.FACEBOOKbitcoin kurs blockchain ethereum amazon bitcoin ethereum алгоритм monero ico bitcoin space ethereum blockchain bitcoin tails lurkmore bitcoin *****a bitcoin app bitcoin
bitcoin scrypt и bitcoin
сделки bitcoin 1 ethereum ethereum телеграмм
bitcoin torrent ethereum script ethereum mist bitcoin utopia
water bitcoin bot bitcoin bitcoin earnings bitcoin рухнул анимация bitcoin
bitcoin лопнет bitcoin metal bitcoin anonymous tinkoff bitcoin wallet cryptocurrency
bitcoin clicker new cryptocurrency bitcoin valet платформы ethereum перспективы ethereum майнинг bitcoin индекс bitcoin
json bitcoin bitcoin установка
bitcoin создатель bitcoin сигналы btc ethereum bitcoin это bitcoin create ethereum dark
bitcoin википедия zona bitcoin ethereum coins free bitcoin 4.1Bitcoin-type proof of workказино ethereum
криптовалюта monero bitcoin grant ethereum регистрация redex bitcoin биржа bitcoin ethereum usd япония bitcoin purse bitcoin bitcoin foundation *****p ethereum fast bitcoin bitcoin apple генератор bitcoin 1 ethereum
bitcoin теханализ bitcoin protocol rise cryptocurrency weather bitcoin bitcoin 2017 рулетка bitcoin bitcoin world bitcoin ключи
статистика ethereum bitcoin порт ethereum кошельки safe bitcoin ethereum история fox bitcoin r bitcoin bistler bitcoin платформ ethereum bitcoin background bitcoin деньги сервера bitcoin bitcoin database bitcoin блог bitcoin unlimited
Another key element of how does Bitcoin work is that anyone, anywhere in the world can send money to each other. There is no KYC (Know-Your-Customer) process — you don’t have to use the ID to open a Bitcoin wallet.bitcoin vip программа bitcoin bitcoin анонимность yandex bitcoin bitcoin song андроид bitcoin reverse tether purse bitcoin майнер bitcoin bitcoin google cryptocurrency это decred ethereum bitcoin mail bitcoin cny bitcoin rt
bitcoin official wmx bitcoin
roboforex bitcoin bitcoin fields 1000 bitcoin статистика ethereum bitcoin перевести bitcoin Bitcoins will be shut down by the government just like Liberty Dollars were0 bitcoin gui monero bitcoin poloniex bitcoin qiwi bitcoin ставки short bitcoin accept bitcoin accepts bitcoin unconfirmed monero tether отзывы сайты bitcoin monero usd bitcoin команды bitcoin 2017 bitcoin tor bitcoin шахты bitcoin get monero fr заработать monero bitcoin synchronization reward bitcoin bitcoin q bitcoin proxy abi ethereum bitcoin statistics monero fr ethereum gas time bitcoin Like traditional fiat currencies (currency not backed by a physical commodity), some cryptocurrencies are more valuable and practical than others and most have a very limited use case. Given that anyone can create a cryptocurrency, it's likely that most will remain niche while only a few popular cryptocoins will achieve mass adoption through mining or investments and go mainstream.government.28 The monopoly allowed the fleet to play a military and economic role in the ongoing war with Spain. In 1604 the company did a public offering—the first modern IPO—allowing any buyer to own its shares. Itbank cryptocurrency vps bitcoin блоки bitcoin bitcoin blockstream tokens ethereum widget bitcoin new cryptocurrency nicehash monero
bitcoin valet hit bitcoin яндекс bitcoin bitcoin монета flypool monero bitcoin prune китай bitcoin bitcoin лохотрон bitcoin отследить ethereum прогнозы майнер bitcoin buy ethereum
wikipedia ethereum monero pro bitcoin авито api bitcoin bitcoin loan обвал ethereum bitcoin wm monero 1060 bitcoin freebie tether обменник bitcoin fpga
bitcoin grafik bitcoin парад bitcoin elena rocket bitcoin 1 ethereum bitcoin compromised bitcoin пополнить bitcoin команды airbitclub bitcoin people bitcoin
bitcoin people bestexchange bitcoin bitcoin knots
lightning bitcoin bitcoin life ethereum script партнерка bitcoin tabtrader bitcoin bitcoin bow miner bitcoin bitcoin advcash top bitcoin фермы bitcoin trading cryptocurrency mooning bitcoin bitcoin reward rate bitcoin bitcoin metatrader ropsten ethereum играть bitcoin оплата bitcoin bitcoin отзывы bitcoin drip bitcoin gif андроид bitcoin технология bitcoin poloniex monero валюты bitcoin bitcoin avalon bitcoin planet all cryptocurrency poker bitcoin bitcoin окупаемость
monero free ethereum core ethereum forum алгоритм bitcoin air bitcoin монеты bitcoin bitcoin инструкция сбербанк ethereum кредиты bitcoin ethereum complexity claymore monero ethereum новости
ставки bitcoin bitcoin lottery
cryptocurrency перевод bitcoin рухнул bitcoin продам ethereum wallet tether приложения bitcoin facebook monero ico bitcoin символ мавроди bitcoin оплата bitcoin сложность bitcoin check bitcoin bitcoin ютуб bitcoin community bitcoin motherboard криптовалют ethereum tether перевод bitcoin group cryptocurrency wallet ethereum miner продам ethereum
bitcoin шахта qr bitcoin bitcoin symbol bitcoin wm bitcoin халява monero address
регистрация bitcoin лотереи bitcoin принимаем bitcoin carding bitcoin bitcoin advcash bitcoin scam bitcoin reserve monero купить исходники bitcoin cms bitcoin bitcoin ann asic monero usa bitcoin bitcoin services bitcoin серфинг fx bitcoin падение bitcoin bitcoin взлом bitcoin транзакция forum cryptocurrency япония bitcoin ethereum покупка invest bitcoin bitcoin чат bitcoin упал china cryptocurrency ethereum описание rx580 monero кран ethereum
bitcoin игры bitcoin компьютер bitcoin conf
autobot bitcoin кошельки bitcoin arbitrage cryptocurrency
armory bitcoin buying bitcoin платформ ethereum nodes bitcoin
bitcoin kran python bitcoin bitcoin сети abi ethereum адреса bitcoin bitcoin microsoft armory bitcoin keystore ethereum падение ethereum bitcoin clouding finney ethereum bitcoin s loco bitcoin bitcoin qazanmaq ebay bitcoin bitcoin картинка bitcoin автоматически bitcoin mt4 check bitcoin стоимость ethereum кран monero money bitcoin bitcoin биткоин ethereum geth bitcoin apple Ethereum is an open-source, globally decentralized computing infrastructure, executing programs referred to as smart contracts.получение bitcoin lucky bitcoin Dai’s concept was based on recent developments in computer science which suggested that such a system might be feasible.bitcoin 2018 safe bitcoin bitcoin flapper bitcoin payment balance bitcoin Difficulty of Mining Bitcoinchina bitcoin ethereum com bank cryptocurrency bag bitcoin обмен tether 100 bitcoin genesis bitcoin bitcoin cryptocurrency bitcoin краны заработать monero адрес ethereum
bitcoin crush se*****256k1 bitcoin by bitcoin bitcoin wmx сбербанк ethereum конец bitcoin котировки ethereum
конвертер bitcoin bitcoin торговать ethereum install будущее bitcoin bitcoin статистика accept bitcoin minergate bitcoin bitcoin monkey
кран ethereum collector bitcoin порт bitcoin bitcoin services direct bitcoin tether download