Bitcoin is commonly referred to as a cryptocurrency, a digital means of exchange. It was developed by a set of anonymous authors under the pseudonym of Satoshi Nakamoto, and began operating in 2009 as a community project, without any relationship with or dependency on any government, state, company or body. The value of bitcoin is formed by a complicated system of mathematical algorithms and cryptography and it is not supported by any central bank or authority. Bitcoins are essentially accounting entries in a large database called a blockchain, which is unique but replicated in millions of computers connected to the internet. Bitcoins can be exchanged almost instantaneously for any currency and can be used for payment. The system has numerous pros and cons, and many central banks insist that bitcoin is not a currency but a highly speculative and high-risk asset. In reality it is reasonably quick and easy to buy cryptocurrencies but the exchanges make it harder and costlier to sell them.