Few technologies have the ability to stir passionate online debate and baffle the vast majority of the population as Bitcoin. The virtual currency has been a constant source of interest and confusion since it thrust itself into the mainstream more than five years ago.
But interest in bitcoin is now greater than ever. Its value has soared to above $4,000, a new high point, turning some people who hoarded vast amounts early on into millionaires.
But why? Is bitcoin the future of currency? Is it currency at all? What is it for? And should I buy some? Read on to have your questions answered.
What is bitcoin?
Bitcoin is a digital currency created in 2009 that uses decentralised technology for secure payments and storing money that doesn't require banks or people's names. It was announced on an email circular as a way to liberate money in a similar way to how the internet made information free.
How does it work?
Bitcoin works on a public ledger called blockchain, which holds a decentralised record of all transactions that is updated and held by all users of the network.
To create bitcoins, users must generate blocks on the network. Each block is created cryptographically by harnessing users' computer power and is then added to the blockchain, letting users earn by keeping the network running.
A limit for how many bitcoins can be created is built into the system so the value can't be diluted. The maximum amount is just under 21 million bitcoin. There are currently 15 million in circulation, each of which was worth more than $4,000 ($3,080) at the time of writing.
What affects its price?
The price of a bitcoin has jumped up and down since it first entered the mainstream consciousness in 2013. That year prices rose by almost 10,000 per cent before the collapse of Mt Gox, the biggest online bitcoin exchange, sent it crashing.
Prices slowly crept up after that but have since surged again. This is largely put down to regulators appearing to warm to bitcoin and the rise of initial coin offerings - a way for projects to raise money by selling cryptographic tokens similar to bitcoins. Many sceptics believe we are in the middle of a new bitcoin bubble while advocates say we are just beginning to see the rise of bitcoin.
Who is Satoshi Nakamoto?
Satoshi Nakamoto is the mysterious creator of bitcoin and blockchain. Despite countless attempts to unmask the person or people behind the name, their identity has remained elusive.
There have been numerous unsuccessful attempts by journalists to reveal the bitcoin founder. In a high-profile incident in 2014, Newsweek magazine relaunched with a feature outing Dorian Nakamoto, a 64-year-old Japanese-American man, as the creator. The affair, having fallen apart under scrutiny, ended with a car chase and the real Nakamoto refuting the allegations.
The most recent candidate was Craig Wright, a former Australian academic, who claimed to be the bitcoin inventor. Wright wrote blog posts and gave interviews to Wired, BBC and the Economist in 2015 and 2016 saying he was behind bitcoin.
After failing to provide unquestionable proof, Wright posted an apology message that said: "I believed that I could put the years of anonymity and hiding behind me. But, as the events of this week unfolded and I prepared to publish the proof of access to the earliest keys, I broke. I do not have the courage. I cannot."
How many people use bitcoin?
There are as many as 5.8 million users that have cryptocurrency wallets, according to research from the University of Cambridge, the majority of whom use bitcoin.
What is it used for?
Bitcoin is has a range of uses, including funding companies, investing cash and transferring money without fees. It is commonly associated with criminal activity such as drug dealing, cyber crime and money laundering, since it can be near-impossible to tie a bitcoin wallet to any one individual.
Bitcoin can be spent online and at select retailers in the UK. They include CEX stores, Dell's website, Your Sushi restaurants, and some pubs. A full list of online and offline businesses that accept bitcoin is available here. They can also be withdrawn at a couple of dozen bitcoin ATMs, which can be found here.
Others simply hold their bitcoins, hoping they will accumulate in value and prove to be a lucrative investment. Its price is notoriously volatile, and early investors are now sitting on massive gains.
Should I invest in bitcoin?
Bitcoin is safeguarded against fraud and theft through independent and decentralised set up, as well as being free from transaction fees. It has also given great returns to some investors, with the price jumping from a few dollars at the beginning of 2013 to $1,100 by November. People who invested £2,000 five years ago would now be millionaires.
After a few level years, its dollar price soared again this year, and it has peaked at around $4,200. But the price has also dropped in the past and left people out of pocket. Back in May it fell by $400 in a day.