What is Bitcoin Mining?

What is Proof of Work?

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A proof of work is a piece of data which was difficult (costly, time-consuming) to produce so as to satisfy certain requirements. It must be trivial to check whether data satisfies said requirements.

Producing a proof of work can be a random process with low probability, so that a lot of trial and error is required on average before a valid proof of work is generated. Bitcoin uses the Hashcash proof of work.

What is Bitcoin Mining Difficulty?

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The Computationally-Difficult Problem

Bitcoin mining a block is difficult because the SHA-256 hash of a block's header must be lower than or equal to the target in order for the block to be accepted by the network.

This problem can be simplified for explanation purposes: The hash of a block must start with a certain number of zeros. The probability of calculating a hash that starts with many zeros is very low, therefore many attempts must be made. In order to generate a new hash each round, a nonce is incremented. See Proof of work for more information.

The Bitcoin Network Difficulty Metric

The Bitcoin mining network difficulty is the measure of how difficult it is to find a new block compared to the easiest it can ever be. It is recalculated every 2016 blocks to a value such that the previous 2016 blocks would have been generated in exactly two weeks had everyone been mining at this difficulty. This will yield, on average, one block every ten minutes.

As more miners join, the rate of block creation will go up. As the rate of block generation goes up, the difficulty rises to compensate which will push the rate of block creation back down. Any blocks released by malicious miners that do not meet the required difficulty target will simply be rejected by everyone on the network and thus will be worthless.

The Block Reward

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 25 bitcoins; this value will halve every 210,000 blocks. See Controlled Currency Supply.

Additionally, the miner is awarded the fees paid by users sending transactions. The fee is an incentive for the miner to include the transaction in their block. In the future, as the number of new bitcoins miners are allowed to create in each block dwindles, the fees will make up a much more important percentage of mining income.

What is the Blockchain?

Bitcoin mining is intentionally designed to be resource-intensive and difficult so that the number of blocks found each day by miners remains steady. Individual blocks must contain a proof of work to be considered valid. This proof of work is verified by other Bitcoin nodes each time they receive a block. Bitcoin uses the hashcash proof-of-work function.

The primary purpose of mining is to allow Bitcoin nodes to reach a secure, tamper-resistant consensus. Mining is also the mechanism used to introduce Bitcoins into the system: Miners are paid any transaction fees as well as a "subsidy" of newly created coins.

This both serves the purpose of disseminating new coins in a decentralized manner as well as motivating people to provide security for the system.

Bitcoin mining is so called because it resembles the mining of other commodities: it requires exertion and it slowly makes new currency available at a rate that resembles the rate at which commodities like gold are mined from the ground.

Bitcoin Mining Hardware Comparison

Currently, based on (1) price per hash and (2) electrical efficiency the best Bitcoin miner options are:

  AntMiner S7

 Avalon6

 SP20 Jackson

What is Bitcoin Mining?

How Bitcoin Mining Works

Where do bitcoins come from? With paper money, a government decides when to print and distribute money. Bitcoin doesn't have a central government.

With Bitcoin, miners use special software to solve math problems and are issued a certain number of bitcoins in exchange. This provides a smart way to issue the currency and also creates an incentive for more people to mine.

Bitcoin is Secure

Bitcoin miners help keep the Bitcoin network secure by approving transaction. Mining is an important and integral part of Bitcoin that ensures fairness while keeping the Bitcoin network stable, safe and secure.

What are its characteristics?

Bitcoin has several important features that set it apart from government-backed currencies.

1. It's decentralized

The bitcoin network isn’t controlled by one central authority. Every machine that mines bitcoin and processes transactions makes up a part of the network, and the machines work together. That means that, in theory, one central authority can’t tinker with monetary policy and cause a meltdown – or simply decide to take people’s bitcoins away from them, as the Central European Bank decided to do in Cyprus in early 2013. And if some part of the network goes offline for some reason, the money keeps on flowing.

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2. It's easy to set up

Conventional banks make you jump through hoops simply to open a bank account. Setting up merchant accounts for payment is another Kafkaesque task, beset by bureaucracy. However, you can set up a bitcoin address in seconds, no questions asked, and with no fees payable.

3. It's anonymous

Well, kind of. Users can hold multiple bitcoin addresses, and they aren’t linked to names, addresses, or other personally identifying information. However…

4. It's completely transparent

…bitcoin stores details of every single transaction that ever happened in the network in a huge version of a general ledger, called the blockchain. The blockchain tells all.

If you have a publicly used bitcoin address, anyone can tell how many bitcoins are stored at that address. They just don’t know that it’s yours.

There are measures that people can take to make their activities more opaque on the bitcoin network, though, such as not using the same bitcoin addresses consistently, and not transferring lots of bitcoin to a single address.

5. Transaction fees are miniscule

Your bank may charge you a £10 fee for international transfers. Bitcoin doesn’t.

6. It’s fast

You can send money anywhere and it will arrive minutes later, as soon as the bitcoin network processes the payment.

7. It’s non-repudiable

When your bitcoins are sent, there’s no getting them back, unless the recipient returns them to you. They’re gone forever.

So, bitcoin has a lot going for it, in theory. But how does it work, in practice? Read more to find out how bitcoins are mined, what happens when a bitcoin transaction occurs, and how the network keeps track of everything.

What is bitcoin based on?

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Conventional currency has been based on gold or silver. Theoretically, you knew that if you handed over a dollar at the bank, you could get some gold back (although this didn’t actually work in practice). But bitcoin isn’t based on gold; it’s based on mathematics.

Around the world, people are using software programs that follow a mathematical formula to produce bitcoins. The mathematical formula is freely available, so that anyone can check it.

The software is also open source, meaning that anyone can look at it to make sure that it does what it is supposed to.

So you can’t churn out unlimited bitcoins?

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That’s right. The bitcoin protocol – the rules that make bitcoin work – say that only 21 million bitcoins can ever be created by miners. However, these coins can be divided into smaller parts (the smallest divisible amount is one hundred millionth of a bitcoin and is called a ‘Satoshi’, after the founder of bitcoin).