In 2008 an anonymous idealist published a paper under the pseudonym Satoshi Nakamoto which described a digital currency or online payment system; the system was introduced as open-source software in 2009. Four years later the value of all bitcoins was in the billions of dollars. Bitcoin uses peer-to-peer technology to operate with no central authority or banks; the management of transactions and the issuance of bitcoins is carried out collectively by the network. Because bitcoin is public by design it is not owned or controlled by any government or bank.