A cryptocurrency, crypto-currency, or crypto is a collection of binary data which is designed to work as a medium of exchange wherein individual coin ownership records are stored in a ledger which is a computerized database using strong cryptography to secure transaction records, to control the creation of additional coins, and to verify the transfer of coin ownership. Some crypto schemes use validators to maintain the cryptocurrency. In a proof-of-stake model, owners put up their tokens as collateral. In return, they get authority over the token in proportion to the amount they stake. Generally, these token stakers get additional ownership in the token over time via network fees, newly minted tokens or other such reward mechanisms. Cryptocurrency does not exist in physical form and is typically not issued by a central authority. Cryptocurrencies typically use decentralized control as opposed to a central bank digital currency . When a cryptocurrency is minted or created prior to issuance or issued by a single issuer, it is generally considered centralized. When implemented with decentralized control, each cryptocurrency works through distributed ledger technology, typically a blockchain, that serves as a public financial transaction database.