In a BIS Quarterly Review article, Morten Bech and Rodney Garratt offer a taxonomy of money, with special emphasis given to central bank issued digital and crypto currency. They stress four dimensions:

issuer (central bank or other); form (electronic or physical); accessibility (universal or limited); and transfer mechanism (centralised or decentralised). The taxonomy defines a CBCC as an electronic form of central bank money that can be exchanged in a decentralised manner known as peer-to-peer, meaning that transactions occur directly between the payer and the payee without the need for a central intermediary. This distinguishes CBCCs from other existing forms of electronic central bank money, such as reserves, which are exchanged in a centralised fashion across accounts at the central bank.