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Cryptocurrency
digital medium of exchange using cryptography on a ledger to secure transactions and to verify transfer of ownership / From Wikipedia, the free encyclopedia
Cryptocurrency is a type of currency which uses digital files as money. Often, people create these files using the same ways as cryptography (the science of hiding information). Cryptocurrency users can use Digital signatures to keep the transactions safe, and to let other people check that the transactions are real.[1][2][3] The creators of the first cryptocurrencies made them to be free of government-given currencies.
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No single person controls cryptocurrencies. Instead they are decentralized and controlled by many people.[4] This is different from 'centralized' electronic money and central banks, which a small group of people control.[5] The control of each cryptocurrency works through a distributed ledger (a list of transactions shared by everyone), usually a blockchain.[6] This lets everyone know all of the financial transactions that happen.[7]
Bitcoin, first released as open-source software in 2009, is famous because it was the first decentralized cryptocurrency.[8] Since then, people have created more than 4,000 cryptocurrencies (sometimes called altcoins, or alternative coins). [9]