Bitcoin uses peer-to-peer technology to operate with no central authority or banks; managing transactions and the issuing of bitcoins is carried out collectively by the network. Bitcoin is open-source; its design is public, nobody owns or controls Bitcoin and everyone can take part. Through many of its unique properties, Bitcoin allows exciting uses that could not be covered by any previous payment system.
The system is peer-to-peer, and transactions take place between users directly, without an intermediary.[13]:4 These transactions are verified by network nodes and recorded in a public distributed ledger called a blockchain. Since the system works without a central repository or single administrator, bitcoin is called the first decentralized digital currency.[13]:1[16]Besides being created as a reward for mining, bitcoin can be exchanged for other currencies,[17] products, and services in legal or black markets.[18][19]As of February 2015, over 100,000 merchants and vendors accepted bitcoin as payment.[20]According to research produced by Cambridge University in 2017, there are 2.9 to 5.8 million unique users using a cryptocurrency wallet, most of them using bitcoin.[21]