A cryptocurrency is a medium of exchange, that is designed to work like a currency. Usually, cryptocurrencies use features found in strong cryptography, such as digital signatures to secure financial transactions, control the creation of additional units, and verify the transfer of assets.The first of them were created to be independent of a government-issued currency.
Cryptocurrencies use decentralized controlas opposed to centralized electronic money and central banking systems. The decentralized control of each cryptocurrency works through distributed ledger technology, typically a blockchain that serves as a public financial transaction database. Bitcoin, first released as open-source software in 2009, is generally considered the first decentralized cryptocurrency.Since then, over 4,000 altcoin (alternative coin) variants of bitcoin have been created.