A cryptocurrency exchange, or a digital currency exchange (DCE), is a web-service that provides its customers services for the exchange of virtual currency into various assets, such as fiat or other digital currencies. The platforms usually work solely online, providing transactions in electronic forms and taking fees for them, though there are also some brick-and-mortar businesses that use traditional payment methods. Debit and credit cards, postal money orders and other kinds of money transfers are accepted to make an operation using a DCE. Generally, transactions are made between bank accounts and, only in rare cases, a customer can withdraw their money in cash by using special ATMs. Recently, some decentralized cryptocurrency exchanges have been established which operate using prepaid smart contracts, rather than digital currencies.