Category Archives: Bitcoin

Bitcoin is a peer-to-peer payment system introduced as open source software in 2009 by developer Satoshi Nakamoto. The digital currency created and used in the system is also called bitcoin[note 1] and is alternatively referred to as a virtual currency, electronic money, or cryptocurrency.[6] The bitcoin system is not controlled by a single entity, like a central bank, which has led the US Treasury to call bitcoin a decentralized currency.[7] Economists generally agree that it does not meet the definition of money[citation needed].

Bitcoins are created as a reward for payment processing work in which users who offer their computing power verify and record payments into a public ledger. Called mining, individuals engage in this activity in exchange for transaction fees and newly minted bitcoins.[8] Besides mining, bitcoins can be obtained in exchange for other currencies, products, and services.[9] Users can buy, send, and receive bitcoins electronically for a nominal fee using wallet software on a personal computer, mobile device, or a web application.

Bitcoin as a form of payment for products and services has seen growth, and merchants have an incentive to accept the currency because transaction fees are lower than the 23% typically imposed by credit card processors.[10] The European Banking Authority has warned that bitcoin lacks consumer protections.[11] Bitcoins can be stolen and chargebacks are impossible.[12] Commercial use of bitcoin is currently small compared to its use by speculators, which has fueled price volatility.[13]

Bitcoin has been a subject of scrutiny amid concerns that it can be used for illegal activities.[14] In October 2013 the US FBI shut down the Silk Road online black market and seized 144,000 bitcoins worth US$28.5 million at the time.[15] The US is considered bitcoin-friendly compared to other governments, however.[16] In China, new rules have restricted bitcoin exchange for local currency.[17]

The most important part of the bitcoin system is a ledger that records financial transactions in bitcoins. Recording transactions is accomplished without the intermediation of any single, central authority. Instead, multiple intermediaries exist in the form of computer servers running bitcoin software. These form a network by connecting over the Internet that anyone can join. Transactions of the form payer X wants to send Y bitcoins to payee Z are broadcast to this network using readily available software applications. Bitcoin servers can validate these transactions, add them to their copy of the ledger, and then broadcast these ledger additions to other servers.[18]

Just as a ledger can be used to record transfers of conventional money like dollars, all bitcoin transfers are recorded in a computer file that acts as a ledger called the block chain. Where a conventional ledger records the transfer of actual dollar bills or promissory notes that exist apart from it, bitcoins are simply entries in the block chain and do not exist outside of it.[19]

Maintaining the block chain is called mining, and those who do are rewarded with newly created bitcoins and transaction fees.[20] Miners may be located on any continent and process payments by verifying each transaction as valid and adding it to the block chain.[20] As of 2014 payment processing is rewarded with 25 newly created bitcoins per block added to the block chain. To claim the reward, a special transaction called a coinbase is included with the processed payments.[18] All bitcoins in circulation can be traced back to such coinbase transactions. The bitcoin protocol specifies that the reward for adding a block will be halved to 12.5 bitcoins in 2017 and halved again approximately every four years. Eventually, the reward will be removed entirely when an arbitrary limit of 21 million bitcoins is reached c. 2140, and transaction processing will then be rewarded by transaction fees solely.[21] Fees are optional, but users that pay may have their transactions processed more quickly.[22] Payers have an incentive to include transaction fees because their transactions will likely be added to the block chain sooner; miners can choose which transactions to process[citation needed] and prefer to include those that pay fees.

As of 2013 mining has become quite competitive, and the process has been compared to an arms race as ever more specialized technology is utilized. The most efficient mining hardware makes use of custom designed application-specific integrated circuits, which are much faster and use less power compared to general purpose microprocessors, such as x86 processors.[23] Without access to these purpose built machines, a bitcoin miner is unlikely to earn enough to even cover the cost of the electricity used in his or her mining efforts.[24]

The odds of winning the reward for adding a block to the block chain decrease alongside an increase in the number of miners. Mining is a competitive process, and while many participate, the reward for each block can only go to a single miner. As of 2014 it has become common for miners to join organized mining pools to circumvent this problem.[25] Such pools split the work and the reward among all participants and make mining a less risky endeavor. Even for those who join pools, the cost of the electricity necessary to mine may outweigh the bitcoin rewards from doing so.[24]

The public nature of bitcoin means that, while those who use it are not identified by name, linking transactions to individuals and companies can be done.[26] Additionally, many jurisdictions require exchanges, where people can buy and sell bitcoins for cash, to collect personal information.[27] In order to obfuscate the link between individual and transaction, some use a different bitcoin address for each transaction and others rely on so-called mixing services that allow users to trade bitcoins whose transaction history implicates them for coins with different transaction histories.[28]

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Bitcoin - Wikipedia, the free encyclopedia

This is a question that often causes confusion. Here's a quick explanation!

As a new user, you can get started with Bitcoin without understanding the technical details. Once you have installed a Bitcoin wallet on your computer or mobile phone, it will generate your first Bitcoin address and you can create more whenever you need one. You can disclose your addresses to your friends so that they can pay you or vice versa. In fact, this is pretty similar to how email works, except that Bitcoin addresses should only be used once.

The block chain is a shared public ledger on which the entire Bitcoin network relies. All confirmed transactions are included in the block chain. This way, Bitcoin wallets can calculate their spendable balance and new transactions can be verified to be spending bitcoins that are actually owned by the spender. The integrity and the chronological order of the block chain are enforced with cryptography.

A transaction is a transfer of value between Bitcoin wallets that gets included in the block chain. Bitcoin wallets keep a secret piece of data called a private key or seed, which is used to sign transactions, providing a mathematical proof that they have come from the owner of the wallet. The signature also prevents the transaction from being altered by anybody once it has been issued. All transactions are broadcast between users and usually begin to be confirmed by the network in the following 10 minutes, through a process called mining.

Mining is a distributed consensus system that is used to confirm waiting transactions by including them in the block chain. It enforces a chronological order in the block chain, protects the neutrality of the network, and allows different computers to agree on the state of the system. To be confirmed, transactions must be packed in a block that fits very strict cryptographic rules that will be verified by the network. These rules prevent previous blocks from being modified because doing so would invalidate all following blocks. Mining also creates the equivalent of a competitive lottery that prevents any individual from easily adding new blocks consecutively in the block chain. This way, no individuals can control what is included in the block chain or replace parts of the block chain to roll back their own spends.

This is only a very short and concise summary of the system. If you want to get into the details, you can read the original paper that describes the system's design, and explore the Bitcoin wiki.

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How does Bitcoin work? - Bitcoin - Open source P2P money

Make way, bitcoin: A competing digital currency is angling for the spotlight.

Merchants and investors are taking notice of litecoin, pitched by its developers as cheaper to generate, more plentiful and easier to use for small transactions than bitcoin. While prices for both have slid since a surge late last year, litecoins remains about 490 percent higher than six months ago, compared with about 140 percent for bitcoin. Daily litecoin transactions also have climbed faster.

The total value of litecoins available for use ranks second only to bitcoins, according to CoinMarketCap, a website tracking more than 200 digital currencies. That status has helped make litecoin an obvious alternative for investors and enthusiasts seeking new opportunities to profit from virtual money.

Litecoin right now is where bitcoin was the same time last year, Michael Curry, co-founder of Canadian digital-currency exchange Vault of Satoshi, said in an interview. As people are becoming more familiar with bitcoin, they are starting to see there are other coins out there.

Bitcoins jumped from about $13 at the start of last year to more than $1,200 in December, then slid to about $490 late last week, according to CoinDesk, which tracks prices across key exchanges. Litecoins, which surpassed $48 in November, was trading for about $12 last week, according to data from exchange BTC-e.

The average number of daily transactions in litecoins this month is 155 percent greater than Octobers level, according to CoinDesk data. That compares with a 19 percent increase for bitcoins. Daily transactions in bitcoins this month still outnumber those in litecoins almost sevenfold, the data show.

Technology enthusiasts and venture capitalists are pitching digital currencies as fast and cheap alternatives to traditional financial systems, in which middlemen such as networks, merchant acquirers and banks take a cut. Backers also argue that instruments such as bitcoin may be of use to people and businesses in countries with unstable currencies.

Litecoins are drawing notice in part because they can be mined more cheaply than bitcoins. The process uses computers to solve software problems and unlock new digital coins. While bitcoin speculators compete with increasingly expensive machines, litecoins were designed to be efficiently mined with consumer-grade hardware, even if some miners prefer powerful processors.

Sam Cole, co-founder of KnCMiner, one of the biggest mining companies, said equipment used for mining litecoins and similarly designed alternative currencies now accounts for 60 percent of sales.

The maximum number of litecoins that can be mined is four times more than that for bitcoins, potentially making them more attractive to users and miners. Miners have more rewards to go around, while consumers may see litecoins as more affordable, even if bitcoins are typically spent in pieces.

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Bitcoin runner-up Litecoin emerges as low-price challenger

If you own an Android, your phone might be mining bitcoin without you even knowing it.

Five apps were recently removed from the Google Play store after they were discovered to be covertly using Android devices' to mine bitcoin.

Mining requires a lot of computing power to solve complex calculations in order to create more bitcoins. To get the job done, miners usually create systems with many computers.

But now, it seems that at least one miner has turned to malware to take advantage of unsuspecting users and add their mobile devices into his or her mining system.

The mining apps that were recently removed worked by tricking users into downloading them by advertising themselves as wallpaper apps. Users thought they were getting an app with cool smartphone background images, but they were also getting an app that secretly used their device to mine bitcoin.

While users performed other tasks on their devices, the apps worked out bitcoin mining calculations in the background, draining users' batteries faster than normal.

Fortunately, the apps were removed by Google before any of them were downloaded by more than 500 users. The apps were first identified by Lookout, a company that makes security apps for mobile devices.

"Phones truly are tiny computers in your back-pocket or purse," Lookout said in a blog post. "These devices are becoming more and more powerful and people are starting to come up with ways to take advantage of that power."

Lookout has a system that is constantly analyzing new apps for malware. It identified suspicious factors within these five apps, leading the company to further look into them. Lookout confirmed that they were malware apps mining bitcoin and then notified Google.

Lookout said it expects to see more mobile mining malware apps in the future.

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Google removes malware Android apps used to secretly mine bitcoin

Image: Courtesy of Joshua Alvarez/The Hatch Agency

Bitcoin may be the future of digital money, but it has a big problem here in the United States: why use it to buy anything when millions of merchants already accept debit and credit cards?

Today, if you want to buy a bottle of lemonade with bitcoins, you need to scan a QR code with your phone or email a long bitcoin address to the seller. For most people, buying with bitcoins just isnt as easy as Visa or MasterCard.

You just have one card that you can use everywhere without restrictions.

But thats set to change in the next two months. Xapo, a company that offers online bitcoin wallets, says its two months away from introducing the first debit card that will let you spend your bitcoins at any place that takes Visa or MasterCard.

Its a sign of bitcoins growing maturity, and a look at how the digital currency is slowly integrating with the mainstream financial services industry, thanks to a raft of venture-backed bitcoin startups that are now coming online. There are a few other companies that offer prepaid bitcoin cards, but some of them have a fly-by-night feel. Xapo, it seems, is the first to really link your online bitcoin wallet to a card, andbacked by $20 million in VC fundingits on far firmer footing. Unlike others, it also operates out of the United Statesthough its incorporated in Hong Kong.

Heres how it works. Xapo, a bitcoin wallet provider, is in the process of becoming a debit card issuer on one of the major credit card networks. That means that, like your bank, Xapo, can issue you a debit card number and expiration date. You get the card number for free. If you want them to send you some plastic so you can gas up or buy beer at a corner store with your bitcoins, then theyll charge you $15.

Image: Courtesy of Joshua Alvarez/The Hatch Agency

When you use the Xapo card, the credit card number checks in with Xapo, which approves or declines the transaction, depending on how much bitcoin you have in your wallet. It then sells the bitcoin on the Bitstamp exchange and pays out the merchants just like any other card issuer.

You just have one card that you can use everywhere without restrictions, says Wences Casares, Xapos founder and a veteran of the digital payment space.

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The Worlds First Bitcoin Debit Card Is Almost Here