Digital currency, or cryptocurrencies, are digital forms of money that exist only in an electronic form. They use cryptography to secure transactions and generate new units of currency, thus eliminating the need for a financial intermediary, such as a bank. Digital currencies are decentralized, meaning that no single organization or government controls them. Instead, they are controlled by a network of users, who review and validate each transaction. Digital currencies can be used to purchase goods and services online, and are becoming increasingly popular as an alternative to traditional forms of money.