Cryptocurrency is a digital asset designed to work as a medium of exchange that uses cryptography to secure its transactions, control creation of units, and verify transfer of assets.  Cryptocurrencies use decentralized control for production and transaction.  There is no state-controlled or cental bank to determine supply and value. Transactions move through the blockchain, which is a public transaction database that functions as a distributed ledger.  Bitcoin, created in 2009, was the first decentralized cryptocurrency, and has been followed by many others such as Ethereum, Tether, Binance Coin, or Dogecoin.